Ed

qntm

It, Robot: 1

...So in the end, we - this is me and Ed - said "to hell with moisture detectors" and built the giant robot instead. We used junk that was lying in the Technology workshop. Old capacitors and CRTs and junk. It was a monster of a machine. It must've been about fifty feet tall. It ran, it jumped, it could fall a thousand feet and take a cruise missile to the chest with no damage. Stayed active for 1000 hours - not like those cheesy ones with external power cables - before needing recharging and could be piloted completely by remote control. As for weaponry, well, you were looking at twin chain guns, bazookas, a rapid-fire armour-piercing rocket launcher, tactical nuclear missiles... the whole Christmas family gift set. Oh, and Magnetic Physics loaned us their railgun, which was nice of them.

So we took it to the DOD and said "Hey, look what we've got!" and tried to sell it to them. But they said "yeah, we've got one too" even though we knew they didn't really, and didn't buy it. So we're left with this fifty-foot robot on our hands. The university said they needed the car park back, so we had to put it in Ed's backyard. We were well annoyed, especially Ed.

The alien invasion started later the same day. I am absolutely not kidding. What are the odds? We finished building a huge weapon of mass destruction just at the EXACT same moment that a massive alien army arrives. Second time that year!

As a number of unfortunate aircraft pilots discover, all our "conventional weapons" are totally useless against their "shields", because they "just absorb the energy to make themselves stronger" (yeah, right). So, predictably, a couple of hours later the DOD comes knocking on Ed's door saying "Hey, could we like, borrow your amazing, flying, all-conquering gigantic robotic war machine?" And Ed goes "Use the one you've got" and we laughed in their faces, coz it served them right.

I couldn't help thinking it was a bit unfair of us, to doom mankind just to get back at the black suits. But Ed turns around, reassures me. "It's okay," he says, "I've been practicing Mechwarrior for months." Which is true. He's been playing that game obsessively since before we even starting building the mech. I haven't been watching too closely but I know he's been getting rather obscenely good at it. So when he shows me the keyboard and mouse interface that he's worked out, I figure this could be a pretty interesting week.

It, Robot: 1.5

You may recall the alien invasion I mentioned.

They blew up our robot! We were WELL annoyed.

After we heard the invasion had started, Ed got the keyboard/mouse interface rigged up and launched the mech as soon as he could. The USAF was already at the scene of the conflict, of course, fighting a losing battle, so when we arrived we got a lot of enthusiastic greetings. The pilots started rallying behind Ed, defending him while he cut swathes through the hundreds of enemy fighters. Rockets, chain guns, explosions, dogfights, it was a heck of a firework show. And we all thought Ed was doing a great job, flying it, as he was, from his bedroom computer.

But there were just too many of them. News networks estimated at least 2,000 drone fighters in the immediate airspace, and the mech was taking hundreds of hits by the minute. It added up. Even the toughest armour was worn away eventually. Vital systems started to go. Ed fought bravely, firing all of his homing rockets before the last communications module was destroyed. Then the machine froze, collapsed, and exploded. I mean, nuts. That was like our last hope.

Five minutes later Ed answers the phone. "It's some guy from America," he says. He gives me the name and I check up on the internet. It's the world's #1 ranked Mechwarrior player. Suddenly I'm interested. I listen in on the phone call.

He says he thinks Ed didn't do too badly, but next time, he wants to have a go. Is that okay?

Bleep. Call waiting. I drift away to check my email while Ed answers more calls. I've got mails from a dozen professional gamers asking for a turn. A hundred instant messaging windows have popped up. They all saw the news broadcasts. They all want to help fight the aliens.

"It's the DOD again," says Ed, bringing the phone over. "They really want the design for the mech, because they know it's their only shot. They saw the battle today. They reckon that the principle will work; all we need is more mechs. And they're offering to make a production line. Only problem is, none of their pilots have any experience with giant robots. We'll have to find our own."

And I'm thinking: Holy cow, it's actually happening. Thousands of gamers united, pooling their mutual skills to fight for humanity's survival in a real-life war against marauding extra-terrestrials. Only You Can Save Mankind. It's every gamer's life-long dream. A vindication of their so-called "wasted youth".

"Will they give us a T3?" I ask.

"OC-192," says Ed.

I grin like a idiot.

The Annoying Orange Orb Outside My Window Each Morning

My mate Ed has been working on a new project for the last week or so. He hasn't done the classic "never comes out for food or sleep" routine, because, unlike all those other scientists in the movies, he isn't an idiot. But he did keep the basement door locked (where our workshop is), and he did refuse to tell me what he was doing. Ed has done this before. Usually the results, though utterly, utterly useless, make great conversation pieces, but sometimes they are explosive or, on one memorable occasion, sentient, so I was in two minds about what to expect this morning when he announced that he was done, and asked me down into the basement to show me.

I couldn't see anything new in there except for a single, one-inch long component rocker switch in the middle of the otherwise empty worktop. It had a red wire and a black wire soldered to the contacts underneath, trailing off the table into some dark corner of the lab. Ed was sitting in a chair at the worktop, with the switch under one hand and a stopwatch in the other. As I descended the stairs I saw him turn the switch on and start the stopwatch simultaneously. He counted to five and then turned it off, before he looked up.

"Is that all of it?" I asked, sitting in the chair opposite him.

"Yes," said Ed bluntly, smiling broadly at me. There was a pause. I was half-inclined to believe him. Ed is the kind of guy with whom, after a while, you learn to take nothing for granted. But he shook his head and continued, "No, this switch is connected to one of Jazz's network ports." He nodded at Jazz, the extremely ancient Acorn personal computer that has been sitting in the corner of our basement for the last four or five years. "As you know, Jazz's other network port runs directly into the university data network. That network has a large number of other computers on it, including among other things a pair of Cray supercomputers that serve the Theoretical Physics labs..."

I know all this already, and Ed knows I know. Most of his projects begin with a speech exactly like this, right up to "Theoretical Physics labs".

"Now the Crays, as you are probably not aware (unless, like me, you are updated on a minute-to-minute basis of the status of the experiments currently in operation in the Theoretical Physics Centre), are even as I speak involved in running and processing the data from a ground-breaking experiment in a region of physics known as quantum tunnelling. Now, as I recently realised, quantum tunnelling is not all that different from the phenomenon called teleportation..."

I hold up a hand. "Let me guess the rest. You've got some kind of program stored on Jazz. When you close the switch, that's the cue for it to transfer itself all the way over to the Crays, where it forcibly takes over the experiment."

"You have learned well. Yeah, it aborts the experiment currently in progress, and then begins its own sequence of instructions. When I open the switch again, the program ceases and everything goes back to normal."

I nod approvingly. I long ago made the point to Ed that doing bad things to other people's expensive laboratory equipment was not very nice. "So what does the program actually do?"

Ed waves his hands vaguely. "Teleports stuff. It's a bit complicated."

"I saw you already closed the switch."

Ed winks, and checks his stopwatch. "That was one minute and thirty-one seconds ago. Why don't we take a walk outside? The results won't be visible for a few minutes."

"The results will be visible from the street?"

"You'll see. Or not."

Cryptic. Ed takes the stopwatch with him as we head up to the front door. He locks it and we walk out into the suburban street. There is no traffic about but there are a few people going about their business. It's a beautiful day, the sun is shining and it's almost noon.

"You're not gonna blow the whole world up, are you?" I ask Ed. This is not a dumb question. Ed flirts with Armageddon practically on a monthly basis. It's all rather worrying.

"No, nononono. Nothing like that. Something rather more spectacular."

I point at a dark building on the horizon and say, "TPC's that way." I'm still half-expecting some kind of explosion.

Ed shrugs. There's a long pause while we wait under one of the trees that line this street. I sit down on the pavement and enjoy the sunshine. Ed intently studies his stopwatch. We wait for at least five minutes. Nothing happens. I point this out to Ed.

"It'll happen, it'll happen," said Ed. "What's the speed of light these days?"

"Uh... Two hundred and ninety-nine million, seven hundred and ninety-two thousand, four hundred and fifty-eight metres per second by definition," I recite. I'm a geek. You know this.

"And the radius of the Earth's orbit?"

"Just under a hundred and fifty million kilometres." I frown and look up, cogs a-whirring in my head. Ed counts from the stopwatch.

"Eight minutes fifteen, eight minutes sixteen, eight minutes seventeen-"

The Sun goes out.

There is no sound, there is no descending "pyeeow" tone of power generators spinning to a halt, but suddenly the world is plunged in total darkness. All the birds stop singing. I hear a very distant honking as cars screech to a halt in the middle of the road. There are stars visible overhead. My eyes aren't adjusted to the darkness - I can't see a thing, least of all Ed, but I can hear him beside me, laughing uproariously like the lunatic genius he always was.

"Well, so much for the rumours of the Daystar," is the funniest line I can come up with on such short notice.

Five seconds later the Sun came back on again, just as Ed promised. We went back inside and performed the traditional post-experiment ritual of getting some popcorn and watching the news reports about it on TV. Ed, the forward-thinking guy he is, already has a blank videotape cued up. The press seemed to be pretty excited about this one, and personally I didn't blame them.

"Are you gonna tell them who did it?"

"Probably not," said Ed. "See, if I did, I'd get loads of credit for it, but they'd probably lock me up as well. Whereas if I leave it as a total mystery, I've got this great gag lined up for Christmas 2012..."

Turn On, Tune In, Drop Out

"As we all know, the security on the vast majority of the internet's component computers is terrifyingly flawed at best and non-existent at worst..."

Ordinarily, Ed would give the introductory speech to a newly-completed software-related project of his in the short period of time while his computer boots up. Unfortunately, we recently got hold of a computer which, for reasons best left unelaborated-upon at this point, boots up completely before you can even let go of the power stud, so this kind of ruins the moment.

"I was vaguely aware of this," I say to Ed. We are standing in front of Blues, which is what we decided to call the new machine. It's a brand new model, top of the line. Specs of a machine you wouldn't expect to be around for another twenty years. (Don't ask.)

"So it was relatively easy for me to allow my most recent project, which takes the form of a worm, to work its way through to roughly a hundred million different PCs."

"Worm, what worm?"

"Just chill, it's nothing dangerous. And it self-destructs right afterwards, leaving no harmful traces on anybody's computer."

"Then why have you spread it around so far?"

"For fun. Because it's what I do. I had this crazy idea while watching The Matrix one time, and it kind of snowballed."

Ed gets crazy ideas a lot. That's not unusual; most of us get a crazy idea at least once a day, it's what keeps the world spinning. The only problem is that Ed has a) an obsession with hard science fiction, meaning when he gets a crazy idea, he gets a CRAZY idea and b) almost supernatural engineering, scientific, technological and programming ability, meaning that he is rather good at putting his crazy ideas into practice.

I'm trying to teach him how to avoid letting them "snowball", as he describes it, but my own curiosity gets the better of me almost every time. I mean, who wouldn't want to help build and pilot a giant robot against an army of marauding aliens? Did already I tell you about that? I think I did.

"And what crazy thing does it do?"

"No one can be... told what the worm does..."

"Skip it."

"Bah."

I take a seat. I am nervous, but not scared; for Ed is crazy, but not homicidal. And he doesn't usually make mistakes. Well, not often. Well, there was that-

"You ready?" Ed reaches in front of me and types something at the command line. "I'm activating the worm all over the world simultaneously."

"Will this hurt?"

Ed thinks about this one for rather longer than I would have deemed necessary. "No," he concludes.

Mmmmmmmm.

The program runs. Prompt onscreen.

Attention all users.
We are now undergoing scheduled downtime.
You will be logged out for one minute
and then logged back in automatically.
Your work will not be lost in the meantime.
Have a nice day.

5

4

3

2

1

*logging out*

Screen goes to b/w static. "Is that-" I begin to say to Ed.

Then ALL MY VISION goes to static. I turn my head, but every direction I look it's still static, like my optic nerve just crashed. The static soon turns to plain blackness. A pleasant female voice in my ear whispers, "You have been logged out. Please wait sixty seconds until reinsertion. Thank you."

Suddenly the sensations on my skin change. I'm not sitting in an office chair anymore - more like I'm floating upright in warm water. I thrash about a bit in shock and hit something hard and concave with my knuckles. Ouch. I open my eyes. I'm in a tube, a glass cylinder of thick green liquid, lit from below. There's some sort of tube attached to my mouth, feeding me oxygen. There's a pair of white-coated scientists outside the tube, with clipboards. Taking notes. I reach forward towards them and touch cold glass. The scientists stare back impassively. I look to my left and right, but the room is hidden in darkness. The cylinder is capped off at the top - no way to climb out.

Ed, what the hell did you just log me out of?

*

A blink. A flash. Back in the chair. Back in front of the computer. Back in the real world.

Ed is behind me, saying, "Did you like it?"

I stutter, not quite sure whether I've woken up yet. "What WAS it?"

"Data, encoded into the static. I found you could program someone's sensory responses at a distance using a kind of pseudohypnotic-"

I raise a finger. "Ed, you're making up words again."

"Sorry. It's a bit like hypnosis. Hypnotic suggestion. It goes straight past the eyes and straight into your brain. I could make up any scenario I wanted."

"That's insane! And you just did that to a hundred million different people simultaneously?"

"Well, nearer ten million..."

"And you just conned all these people into believing that they had... that they were brains in vats? Being subjected to an artificial reality?"

"No con involved. For those sixty seconds, that's what they were."

Deep.

An Admin Password For The Universe

"Sweet Newton's ghost!" howls Ed from the basement. His voice is abject astonishment tinged with fear.

This is never a good thing.

Ed seems to have been stamped directly from the comic-book mad scientist mould - last week he raised an Amiga 500 to sentience (although it took us a while to notice; it thinks darned slowly). When Ed gets even slightly worried about anything, it's time to run for the next Earthlike planet.

"What's up, Ed?" I holler back, for I am busy fighting a boss and cannot be interrupted.

"You remember last year when I found a second layer of reality below this one?"

My mind races. I vaguely remember something like that. Ed had remotely hijacked control of the Relativistic Heavy Ion Collider, just out of curiosity. It's a long story. "Yeah... but you said it was completely featureless void, didn't you?"

"That's what I thought, but it's not. You should come and have a look at this."

Odolwa will have to wait. I pause the game and descend into the basement.

*

"So what did you find?"

"Messages," says Ed. "Messages, encoded into the very fabric of reality itself. Absolutely no question about it. It's like a pattern of vibrations in- well, the details aren't important. What's important is that the message is obviously in some kind of language; and there was enough of it for me to translate it.

"I've just finished reading the translation. Look at this: it reads like a piece of software documentation." Ed hands over a chunk of paper. I leaf through it.

The first page is a table of settings. The numbers I don't exactly recognise, but some of the names I do.

"Those settings," says Ed, anticipating my first question, "are fundamental physical constants. The speed of light. The Planck Constant. The gravitational constant. Some others that you won't have heard of. Some others that even I haven't heard of."

Next is a list of instructions for altering the settings. Short one-line commands followed by large tracts of incomprehensible vector equations. This goes on for about forty pages.

"The instructions are extremely detailed. In order to alter the constants, you basically need to access this second level of reality and adjust it in some special way. That involves using some seriously heavy hardware. And when I say 'heavy' I mean heavy - if I'm reading this right, I think we're looking at something like five white dwarfs in a Klemperer Rosette..."

"Sorry, white dwarf stars?"

"And that's just to get access. To actually change the settings, for instance if you wanted to increase the speed of light by a factor of a thousand; well, use your imagination. There's no way mankind will ever get that far, not in a million years. But think about what this means. Our universe is 1) open-source and 2) user-modifiable."

"Are you saying... that God uses Linux?"

"Keep reading."

I leaf through another few pages. "It says here that the settings have been changed. There are comments, too."

"Several times, and by several different people, yes. The comments you see there were written by the changers. There aren't any dates - after all, we measure our time according to the vibrations of a caesium atom, and theoretically, one could adjust the frequency of that vibration as much as you liked. But check out the very last comment. 'The next wave of changes that our race makes to these settings will hopefully result in the spontaneous creation of an entirely new universe from the ashes of our own dead one.' I'm willing to bet that the very last change occurred roughly one quadrillionth of a second before the Big Bang."

I am deeply thoughtful for a moment. "It is my considered suggestion that we don't attempt to mess with these settings."

It, Robot: 2

Mutual friend Jen is visiting the Sam/Ed collective here at Ed's geek "pad" in the suburbs. We are feeding her hot chocolate and cookies. Jen is more geeky than most girls - not geeky enough to actually write her own operating systems, but certainly geeky enough to appreciate the effort when someone else does. At the moment we are trying to persuade her that the rather inferior chatterbot she has been talking to for the last half-hour is, against all evidence, actually sentient.

"It's just an Amiga 500, after all," she says.

"Any Turing machine can emulate any other Turing machine," explains Ed. "Even if it means going at ten to the eight operations per second instead of ten to the seventeen. If you don't believe us, that's fine. Just don't blame us if you let it loose on the internet and we all end up plugged into a--"

At this point a loud alarm starts blaring somewhere in the house. Ed immediately puts down his drink and runs out of the kitchen. Jen and I follow him through to the lounge, where he has quickly taken a position in front of the television, holding the Xbox's controller. On the screen, a pre-rendered cutscene appears to be playing itself out. A gigantic robot is lifting off on two pillars of flame, ascending into the clouds.

"What's this?" asks Jen.

"It's one of these real-time, all-pervading reality game things," I say. "Do you remember Majestic? That game which kind of took place in the real world - you'd get messages from NPCs on your mobile phone, by email, by fax, all involved in sorting out some mysterious conspiracy. Every month you'd have a different adventure. It felt a little too linear for most players, but it was a pretty spooky and enjoyable experience for all concerned. For me, anyway. This is like one of them, on the Xbox this time. Ed and a whole bunch of other subscribers are involved in this real-time alien invasion of Earth. At any hour of the day or night, one of them might get called up to help defend the planet."

By now Ed's robot has flown all the way out of the Earth's atmosphere and the screen has switched to a first-person shot from inside the cockpit. There are various readings and dials and crosshairs and including weapons of unimaginable destructive power. Ahead of him, radar shows a wave of alien invaders circling in fast towards Earth.

I motion for Jen to sit down. "Ed has to stop all the invaders reaching Earth. It's an age-old concept, but pretty addictive."

A preliminary run over the outskirts of the wave reveals the approximate number of enemies involved and attracts a small amount of fire. Ed shoots a couple of the drones, dives around behind the wave and begins to wreak multi-chaingun havoc. Miniature explosions blossom on the screen.

"Scenery's a little dull," says Jen.

"Space is mostly nothing with a dash of hydrogen."

"There's no sound either."

"'s called realism," says Ed, blowing up two larger drones with well-targeted missiles. Earth looms large behind him - weight of numbers mean that this wave is taking longer than usual to take care of.

"Realism? In a game with aliens and giant robots?"

"What can I say, they were going for total immersion, and believe me, it works..." says Ed, manoeuvring dextrously and dodging incoming fire by mere metres.

"Can I have a go? It looks like fun."

"Uhhh, no," I say. "There are high scores and performance records and such 'n' such. It's quite important that Ed wins this round." Ed nods, but keeps watching the screen. According to his altimeter, he's only a hundred and fifty kilometres above western Europe, and descending fast. Beneath him, the scenery is gradually becoming clearer.

"Are you gonna do it?" asks Jen. There are still four drones left on the screen, each carrying a lethal explosive payload, and targeted on a major European city. Ed is undeterred. He moves to a position directly between all of them, and detonates an electromagnetic pulse. The four drones explode in unison. The robot swoops out of its dive and turns back to base, and Ed puts the controller down and leans back in his seat, relaxing considerably.

"You won!"

"Yup," says Ed, rubbing an eye. "Close one, though." He is sweating quite a lot. His hands are shaking slightly.

"Well, I gotta take off," says Jen, checking her watch. "Thanks for the cookies."

"No problem," says Ed as I see her to the door. We wave through the window as she walks home.

"Nice save there, Sam," says Ed. "Quick thinking."

"Thanks. We're gonna have to tell her one day," say I. "She's not an idiot, and she'll be very upset if she finds out on her own. Are you okay? Need a lie down? That was a close-run thing."

"I'm fine," says Ed, gradually recovering his composure. "But I think they got to within a minute of ground zero that time. That's the closest they've ever got." He looks up at me and sighs. "I could sure make use of that huge base of subscribers you mentioned."

Overhead, there is a dull roar as the robot comes in to land.

The Best Thing Since Sliced Bread

I'm busy cutting some slices of bread when Ed pops his head into the kitchen. "Do you know what an Einstein-Podolsky-Rosen bridge is?"

"Uh-oh," I observe, putting them in the toaster.

"Harsh," says Ed, the man the light from whose greatest mistakes will not reach Earth for another two million years. What a day that was.

"All right. Yes I do. Where is it, where does it lead, and how can we safely dispose of it without endangering the universe?"

"Come and have a look."

"I'll come down when I've made my omelette," I reply, whisking the eggy mixture one last time and pouring them into the frying pan. Ed leaves.

Ten minutes later I descend into the basement, fork in one hand, food in the other. Ed is standing next to what appears to be a medium-sized red plastic hula-hoop. It is mounted in a large set of metal circles allowing it to rotate in all planes. It is also surrounded with black and yellow tape at a distance of roughly four feet - arm's length.

"That's it?"

"This is it," says Ed. I'm tempted to ask where the machinery is, but knowing him it's probably in Palo Alto, or squeezed into a small side-universe parallel to this one.

"Where does it go?"

"Well, unfortunately, it can't go anywhere yet. There needs to be a receiver device, which I haven't built yet. It's like the first telephone - useless until you invent the second one. However, what I can do is make it lead to itself, sometime in the future. Ten seconds into the future, to be precise."

"Hmm. Cool. Why is it cordoned off?"

Ed switches the thing on and the surface turns pitch black. "It basically functions like a trapdoor ten seconds forwards in time. Nothing can come back the other way - that would result in an effect preceding a cause, which would cause the universe as we know it to cease to exist, with potentially devastating consequences. So from this side of the wormhole, it will always appear pitch black, because no photons can come through from the other side, dig? The reason it's cordoned off is in case you stick your finger through. Nothing comes back. Not even the electromagnetic forces which hold molecules together in solids. You stick your finger through, you pull it back, you've lost your finger. Ten seconds later, if you're quick, you can catch your severed finger in a bucket of ice as it reappears at the far end."

"What if you jumped through really quick?" I ask, taking a bite of toast.

"Blood flow in half of the veins and arteries in your body would be momentarily forced to stop, you might end up misshapen or missing a limb or with transcription errors a la Timeline, so even if you did survive, it'd probably be like a hammerblow through your entire body. But worse than that, nerve impulses and synapse firings in your brain would all be momentarily stopped as your head passes the wormhole terminus. I'm not a brain specialist-"

No kidding, I think, mouth full.

"-but I think it would probably kill you."

"Comforting to know. Well, more comforting than not knowing it could kill you," I remark pointedly.

"Oh, come on. I told you, that wasn't my fault. Those Haitians sold me impure palladium. Anyway. We've had this argument. Watch the tennis ball," says Ed, throwing a ball through the portal. It flies into the blackness and vanishes.

We go around to the other side. "At the other side of the hoop, we can see everything that was happening on the far side of the hoop ten seconds ago. Sound, being a longitudinal pressure wave, doesn't come through very well, but light seems to work okay," says Ed, as the Ed on the other side says something to the Sam on the other side, picks up a tennis ball, and throws it through. I catch it. It's the strangest experience. Like catching a ball that flew out of your television.

"Funky," say I. "And the applications?"

"Well, there's one I thought of. Nothing passes through in the opposite direction, right? Including gravitons. Gravity can't penetrate the wormhole. It's not very obvious when the ring is vertical, but..." Ed manipulates a remote control and turns the hoop horizontally, so the wormhole leads downwards. "This way, it's easier to see. The way to think about it is as if the whole Earth was glowing white, and the ring is your only shadow. So you can see there's a small cone-shaped area above the wormhole which is in gravity shadow. Zero gravity." He demonstrates, picking up the ball with a long set of tongs and gently placing the tennis ball in mid-air over the middle of the hoop. It stays there, rotating gently in mid-air. "So you see, we could make huge rooms that are completely weightless just by constructing a big ring wormhole underneath. The gravity even becomes smoothly stronger towards the edge. Funky indeed."

"But also astoundingly dangerous."

"That's what you say about everything," counters Ed. "There was one other cool application I thought of. In fact, this was why I started building it in the first place. Imagine you had like twenty of these rings, and you stacked them up into a cylinder, and then you turned it horizontally. What have you got?"

"Uh... a portal two hundred seconds into the future?"

Ed glares at me. "No... I can change the time displacement to anything I want, actually. Keep guessing."

"Oh come on, man, I can't see into your mind. Stop-motion photography? A way of temporarily storing really long things in a really short space? Ooh! You set the timer for a few months and you've got a way to keep your kids from opening their Christmas presents ahead of time!"

"No! Think about it! You put something inside the cylinder of wormholes, turn them on for a fraction of a second, turn them off again... what have you got?"

"...The world's most ludicrously advanced bread-slicer?"

Ed grins the enthusiastic grin of the irretrievably insane.

Be Here Now: 1 of 5

I answer the door to two smartly-dressed, sunglasses-wearing men in black. They flash ID cards at me. "Agents Mulheardy and White, CIA," says the one on the left.

I shout over my shoulder, "Ed! It's for you!"

"'Kay!" he responds, and in the following few seconds, a particularly sensitive ear might detect the sound of every computer in the house performing emergency crash backups to a server in Ecuador, and beginning low-level formatting of all their drives.

I let the two agents in and offer them a cup of tea. They decline.

"What's happening?" asks Ed, joining us as we gather in the kitchen.

"Can you identify these individuals?" asks Agent Mulheardy, opening his briefcase and presenting us with a large, full colour photograph of a pair of men, both grinning cheesily, in front of a background of horizontal lines indicating their heights as 5'11" and 6'4".

"That's us," observes Ed.

"This photo was taken forty-eight hours ago at a top secret United States government research facility underneath Mount Kerrig in Nevada. The two individuals in the picture are still being held in custody there."

Ed inhales deeply. "Given that (technically) neither of us have left the United Kingdom in over twelve months, is this picture explainable due to clones, robots, lifelike dummies, time travel, lookalikes, long-lost twins, amnesia, aliens, magic or Photoshop?"

"Time travel," says Agent Mulheardy. Ed nods knowingly. "For the last five or so years, the Kerrig Facility has been researching the serious possibility of travelling either backwards or forwards in time. We have been doing this with the help of your research, Eduardo."

"Your name is Eduardo MacPherson?" I ask incredulously, having always known him as Ed.

He shushes me, and asks the agents, "And how long have you been watching me?"

"Since you invented the giant robot."

"Ah, the giant robot. You've been ripping the data directly out of my computers since then?"

"You have no secrets from us, Mr. MacPherson."

"So you know about the--"

"Oh hell yeah. We're all very impressed, by the way."

"What are they talking about?"

"Got the world top score in Puzzle Bobble, I'll tell you about it some other time--"

"Getting back to the subject," says Agent White. "Thanks to the wormhole technology we, aha, 'borrowed' from you, Ed, scientists working at Kerrig have been surprisingly successful in building their time machine. This time last week they finished a prototype machine which should in theory have been able to send an object backwards in time. It didn't work.

"What we were expecting was that a second copy of the object we put into the machine - typically a piece of fruit - would appear in it several minutes before the experiment began. But instead, any object put into the machine to be sent back simply disappeared. That was until around midnight two days ago, when, completely out of the blue, a pair of humans materialised inside it. They identified themselves as Samuel Hughes and Eduardo MacPherson, gave us your address and told us to go and get you."

"To cut a long story short, we need you to come to the Kerrig Facility with us and try to sort out this mess," says Agent Mulheardy.

Ed looks at me and I shrug. We stand to gain little from resisting. "All righty then."

Be Here Now: 2 of 5

"Have you ever built a time machine, Ed?" I ask as we are driven to the airfield where a high-speed jet is apparently waiting for us.

"Thought about it a bundle of times. Even drew up a sketch of the prototype once, but tore it up and set fire to the pieces. The consequences could have been catastrophic and the risk was too great."

"Freeow," I remark. This is Ed talking.

*

One supersonic flight courtesy of the American air force and ten hours later, an elevator door slides open to reveal that the interior of Mount Kerrig in Nevada is air-conditioned, surprisingly well-lit, and wholly un-claustrophobic. Something like a hundred metres below ground, we are shown to a large, white-painted warehouse-like cavern in which what looks like a fully-assembled, operational particle accelerator has been surrounded with enough miscellaneous heavy electronics to build another one. Cordoned off at the rim of the device - most of which runs through the rest of the mountain's interior - is a cuboidal opening which appears to have been made out of an elevator car. Around the place are a handful of white-coated scientists, and - apparently - me and Ed.

Meeting them is the strangest experience. Here is another me - someone who might well know everything about me. I can't help feeling there's a fair bit about me that I'm unhappy with the thought of other people knowing. Ed seems pretty cool with his alternate self, though.

They claim to be time travellers. A series of tests verify that they share our facial features, fingerprints and DNA. They stake a good claim to being us.

Are they? And if so, what do we do about it?

Alternate Ed is apparently as smart as regular Ed, with a few extra bits of knowledge into the bargain - for, as one would expect from one of the world's first time travellers and a dabbler in what I have grown to term "practical science fiction", he has a working knowledge of time travel and time machines. He arranges a meeting so that he can explain exactly what happened at midnight two days ago.

*

Alternate Ed - from now on, I'm calling him "Ed-A" and alternate Sam "Sam-A" - has the attention of quite a lot of Army officers, a dozen scientists, me, Ed and Sam-A. He also has a whiteboard on which he draws expressive - and irreproducible - diagrams while he talks. "Here's the story. The models of time travel that we have all seen presented in the movies Back To The Future, Tomb Raider or even The Terminator are inherently paradoxical and hence flawed. While travelling forwards in time is perfectly legitimate, akin to simply disappearing for a thousand years or whatever, it is impossible to go backwards in time and kill your own grandfather, since your grandfather was not killed at that time. Temporal paradoxes, by definition, cannot come into existence. In short, you can't change the past.

"You can, however, go backwards in time.

"We resolve this by invoking a variation on many-worlds theory." He draws a horizontal line, names it "TIMELINE A" and, with two crosses, marks the year 1900 and the year 2000. "Suppose I want to go back in time a hundred years from the year 2000. I set up my machine, climb in and turn it on. I appear in 1900. Now, as we all know, there were no time machines in the year 1900, and I can't have changed that. What I've done instead is create a new universe. The act of appearing in 1900 "nudges" the universe from timeline A, onto a different track, B." He draws a second line, parallel to the first, names it "TIMELINE B" and marks the years 2000 and 1900 on that line as well. He then draws a dotted line, leading from 2000 in timeline A to 1900 in timeline B.

"In 1900-A, nothing happens. In 2000-A, I build a time machine and go back a hundred years. And I'm never seen again. In 1900-B, something different happens, namely the appearance of my time machine. Now both universes share the same past, but due to my entry in 1900, they now have different futures. How different they are depends on what I do at that point. I could immediately return forwards in time, resulting in only very minor changes to the year 1900, though as we all know, chaos theory would conspire to inflate these. Or I could, for example, find and kill my great-grandfather. Basically, in 2000-B, anything can happen. This can include me-B never inventing a time machine in the first place.

"Every time somebody jumps backwards in time, the universe splits. Every piece of fruit that was sent back in that time machine - which works perfectly, by the way, we brought some blueprints you can check against - did indeed arrive a few minutes before the experiment began... each in a different universe. Whether, in the name of causality, the alternate scientists in those alternate universes decided to proceed with the experiment or not, is up to chance, and there's no way we can find out, but if they didn't the worst that could have happened was that the extra piece of fruit they had lying around went rotten."

Ed-A wipes off the numbers of the years and replaces 1900 with "midnight two days ago", 2000 with "in a week's time" and puts an extra cross between the two in timeline B, marking it "NOW". "Here's where it starts to get interesting. In our timeline, the one which we'll call timeline A, in about a week's time, all of the above theory will be discovered by scientists working at the Kerrig Facility - you guys. Feeling their debt to me, that's me-A, they invite - where's Dr. Dan Streetmentioner's book of 1001 Tense Formations when you need it? - they invite me-A and Sam-A to come here and become the first time travellers. We then travel back in time approximately one week, disappearing from their timeline entirely.

"And reappearing in this one.

"This is timeline B. This timeline split off from timeline A around two days ago at the point when me-A and Sam-A did or did not arrive from the future. That makes you two," he points to me and Ed, "Ed-B and Sam-B. Everyone get it?"

There is a pause.

"I don't understand," says Ed-B.

And this is Ed talking.

Be Here Now: 3 of 5

"Thank heavens somebody else doesn't get it!" exclaim several other people in the room.

"No, no, no," says Ed-B, "not the theory of time travel you explained, that makes perfect sense. What made it be this universe that you appeared in, out of all of totality? The chances against you guys spontaneously appearing here must be something like--"

"--of the order of a googolplex to one. Yes. This is a very, very unusual universe, to say the least, but everything's gotta happen somewhere, you were just the unlucky ones," replies Ed-A.

"There's something else I don't get," says Ed-B. "If you and Sam-A knew all this, why did you agree to come back in time at all? We have friends, family, lives. It's impossible for you to ever, ever return to timeline A, because there is no time travel in timeline A. You've left a massive gap - it'll be as if you mysteriously disappeared one day and never came back. Can you imagine how Mum and Dad are going to react? How could you do that? Both of you!"

Ed-A blinks. "Good question there. Right. Let me explain a little further and come back to you. What we now have here in timeline B is something of a problemo."

"Yeah, like, there's two of us," says Sam. That's Sam-A, not me, I'm Sam-B. This is getting confusing.

"Right," says Ed-A. "There are two of each of us, genetically identical, having precisely the same past up until two days ago, same house, parents, birth certificates, same identities. 'Long lost twins' isn't going to cut it here. Also, Sam and I aren't thrilled with the idea of setting up new identities elsewhere in the world and pretending to be different people. Especially not considering the media attention I've drawn in the past and am likely to draw in the, hah, future - somebody's relatives are bound to notice something sometime, while watching the news."

"So, basically, we want you two to go back in time," says Sam-A. "You go back in time to just before midnight two days ago. You'll never return to this timeline again, leaving just one Sam and one Ed here, and no problem. We'll go back home and pick up where our lives left off, and the status quo in this timeline is happily restored."

"What about us?" I ask. "Won't we end up in timeline... uh, C?"

"Sure, but when you get there, just do exactly as we did here in timeline B. Switch places with Ed-C and Sam-C and pick up your lives where you left off, and everything is hunky-dory."

"Except for Ed-C and Sam-C," I say.

"...Who then go on to displace Ed- and Sam-D, and so on down an infinite chain of alternate Eds and Sams. Do you see how it works? Each pair of us sends the next pair back in time and takes over from them. It's like adding another visitor to an infinite, full, hotel. Just shift everyone down a room. Eventually, it works out fine for everybody."

"Ahhhh, and now I get it," says Ed-B. Now I see why you came back and left everyone behind in your old universe."

"I thought you might," says Ed-A.

"You're not actually the original Ed and Sam," says Ed-B.

"No. That was what you and I both think of as a helpful lie, as I'm sure - well, I know you understand. Our timeline and this timeline and the next one all actually occur somewhere a long way down the infinite chain - so far, in fact, that neither of us are entirely sure why it started in the first place... or, more importantly, when."

"So which iteration are you?"

"Something of the order of four hundred and fifty billion," says Ed-A. He throws a 3.5 inch floppy disk on the table. "The exact figure is on this disk. We hereby present it to you and charge you with increasing the number stored on it by one, and taking it with you on the next journey."

There is another shocked pause.

"Four hundred and fifty billion," I say.

"The chain goes on forever, Sam," says Ed-A. "Somewhere in the universe, during the infinite repetitions of this same two-day cycle, that number's gonna reach a trillion, then a quadrillion, then a quintillion. Then it's gonna be so big there won't be enough room on the floppy disk to store all the digits. When you think about it, we're actually not as far down the chain as we could be."

"If this disk has survived four hundred and fifty billion iterations of the same two days, that would make it over two billion years old," says the head scientist, a wide, bearded Norwegian.

"It hasn't," says Ed-A, "and it isn't. We replace it with a new one every thousand iterations. What you might find interesting - and if you need any more proof of our story, which I doubt - is that there's another disk in this facility which looks exactly like it, same label and everything. That's the disk that the Ed and Sam six hundred iterations ago decided to use."

Silence.

"Sam and I need to speak alone," says Ed-B, suddenly.

Be Here Now: 4 of 5

Eventually we find an unused interrogation room. I sit in one of the chairs while Ed paces about.

"I don't mind telling you, Sam, this is getting seriously scary," says Ed to me. That was the last thing I needed to hear. Pretty much everything Ed has ever done - the hoop wormhole, the messages woven into the fabric of reality, the switch - has scared me to a greater or lesser extent. But Ed has never been the least bit fazed by his experiments. He always comes up smiling. Until today I kinda thought that was because he was slightly insane.

But Ed is scared too. Ed, destroyer of galaxies, creator of microscopic universes.

"Why?" I ask, against my better judgement.

"The first thing I want to know is why we travelled back in time in the first place. What happens in our future which is so bad that we are willing to leave behind everyone we hold dear and become time travellers? A lot can happen in four hundred and fifty billion iterations of the same two days. Heck, I bet at least a few dozen of us have broken our legs stepping out of the time machine, just by chance. But if the very first Ed and Sam were anything like us, it's possible that what happened to them could happen again, to us. We don't even know how far into the future the first Ed and Sam came back from - it could be a day or a year or a hundred. Is a nuclear war on the cards, or something worse?

"The second thing that worries me is the extent to which our past selves could be lying to us. Even discounting the distortion that even the most carefully-reproduced truths will experience after being copied a half-trillion times, when we look at ourselves, how trustworthy do we seem? Do you think it's likely that at some point in however many iterations, Ed and Sam impulsively decided to spin a web of lies to the next Ed and Sam, chose a number at random, stuck it on a disk and forwarded it to them? And that could have happened a million iterations back. The lie could have been forwarded so many times that neither us nor Ed-A and Sam-A nor the Ed and Sam preceding them even had an inkling of the real truth."

"I wouldn't lie," I volunteer.

"Wouldn't you? Think about chaos theory. The arrival of our alternate selves and the events proceeding on from then can be subtly different in an unimaginable number of ways. Surely it wouldn't be too improbable that the exact circumstances might come about that would persuade us to lie? Even to ourselves?" Ed sees my utterly confused look. "Trust me, it's possible.

"Lastly, I'm not even sure that those two people ARE you and me."

"Oh, come on, now that's just paranoia! What would the Kerrig Facility scientists stand to gain from such deception? They look EXACTLY like us. Their clothes are exact duplicates of ours even down to the little rips and tears. Their speech and mannerisms are ours, although to be honest I didn't think my voice sounded that silly, and they know everything we know - you saw the DNA test results."

"Come on, Sam, I know how to clone people! They could have ripped the cloning technology right from my own computer! And you of all people know how much of a threat to society I am; the odds of me flipping out, deciding to conquer the planet and actually pulling it off are much too risky. Putting me away for good, by means of vaporizing me in that disintegrator-cum-'time machine', would be good for world safety. No, we need some way to be certain."

"Well, how about the time travel passwords?"

Ed claps his hands together. "Brilliant! I should have thought of that!" He rushes to the door and opens it--

Standing outside are Sam-A and Ed-A. "Your time travel password is the phrase 'Laser Squid Nemesis,' says Sam-A to me.

"Yours is a symbol: a Greek capital phi with a square instead of a circle," says Ed-A to Ed. "We were as paranoid as you were. We came to the exact same room and probably had a very similar conversation."

"There's no way you can prove that jazz about there being billions of iterations of us. There's no way the previous Ed and Sam could have proved it to you, for that matter."

"Right, and they didn't. We took it on trust. If we can't trust ourselves, who can we trust?" asks Sam-A.

After an uneasy pause, I eventually relent. "Well, I trust me."

"I guess so," says Ed-B, reluctantly, eyeing his counterpart suspiciously. "Alright. Give us the disk."

*

All this is happening so fast that we might even be able to get back to the UK before the serious jet lag sets in. We have a much-needed meal at the Kerrig Facility canteen and then head back to the time machine room.

Using the (digital) blueprints and technical readouts that Ed-A brought from the previous timeline - blueprints which we KNOW work perfectly due to the fact that both they and their couriers made it here intact - the Kerrig scientists have successfully configured what they are 99.999% sure is a working time machine, capable of admitting the two of us safely. A digital copy of the 'prints has been made and we're taking it back with us, along with the floppy disk and its recently-incremented and possibly arbitrary number.

Ed and I slouch in what is, indeed, a cannibalised elevator car, while around us final checks are made and the component which - while technically containing nothing more entertaining than an Io-worthy quantity of electrical energy - has been affectionately dubbed the "flux capacitor" starts charging.

The final countdown starts. Ed-A and Sam-A have informed us of exactly what to expect in around sixty seconds' time, when we will - if all goes to plan - materialise uninvited in the centre of an incredibly secret scientific installation, set off several alarms and attract the attention of a dozen gun-toting US marines. They say that holding our arms up and saying "we surrender" might be a good idea.

"When are we coming out, exactly?" I ask Ed.

"Well, sending us back to anytime after Ed- and Sam-A appeared in this timeline would only complicate matters unimaginably further, by introducing a third pair of us. Sending us back to the exact time they appeared runs an uncertain risk of us being annihilated by them - or vice-versa - as both of us attempt to materialise in the same location at the same time. So instead we're going back a little further - one nanosecond, to be precise. It's all determined by atomic clocks so there's nothing to worry about on the accuracy front."

"What if they appear right after we do?"

"A googolplex to one."

"Cool."

Pause.

"Hey you guys," says a voice which seems to be coming over the intercom. It's Sam-A. "I just wanted to say, it was pretty cool running into an alternate set of us. Both times. Although the second time is much more enjoyable since you already know what happens, mostly. You'll find out for yourself in about sixteen seconds."

There's a digital readout in the transport chamber, and I glance at it as it ticks downwards. Fifteen. Fourteen. "Yeah," adds Ed-A. "I've got one more piece of advice for my counterpart, though." Ed-B, our Ed, stands up and peers through the tiny window at Ed-A. The intercom is one-way but they still have visual contact, at least. Eight. Seven. "Ed, you listen to this very carefully... are you listening?" Five.

Ed-B nods. Four. Three.

"DON'T MARRY JEN."

"WHAT?"

Be Here Now: 5 of 5

I was kind of expecting a flash of light. Or a tingly sensation or an electric shock or a feeling of intense speed, or at least a jolt. Nope. Nothing.

As it turns out, this is because the instant I closed my eyes, Ed-B managed to hit the emergency abort switch, cancelling the experiment entirely. While the "flux" capacitor discharges harmlessly (but wastefully) into the Earth, he shoulders open the elevator doors and strides across to his alternate self. "What the hell are you talking about?"

"I wasn't anticipating your reactions being quite that fast," says Ed-A.

"They're your reactions, Eduardo my boy," says Ed-B. "What about Jen? We're friends, that's it. You know that's all there is to it. Are you saying we get married? And something bad happens?"

"Um, ahah. Yeah. See, the thing is, this was just supposed to be a sort of joke. I just wanted to make the future more interesting for you. I don't really know if anything happens between us and Jen in the future."

Ed-B gazes levelly at his counterpart from the previous universe for a few moments, and then punches him in the face. As Ed-A reels and tries to regain his balance, Ed-B yells at him. "You're messing with people's lives here, Ed! You're messing with your own life. Let this be a lesson to both of us, since we're pretty much identical; learn to see it from the other guy's perspective. I mean, if I can't empathise with myself I can't empathise with anybody." He turns and heads back to the time machine, where I am still waiting, aghast. "Start it again from step 209," he calls to the scientists in the control room overlooking the machine. He climbs in and shuts the door. The countdown starts again from sixty seconds.

"I can't believe I'd do something like that," says Ed as we wait once again. "I'm not that vindictive, am I?"

"I can't believe it either," I reply. "Maybe it's the fact that you're interfering with your own life that made you think it was okay. I mean, ethically it's a lot like experimenting on yourself versus experimenting on others. Maybe you just thought you could take the joke. Or you were trying to introduce some variety into your alternate self's life."

"My life is varied enough," says Ed. "Bah, I can't second-guess myself. We're both thinking exactly the same number of moves ahead. Well, we'll do it differently when it's our turn..."

The timer hits zero, but there's still no flash of light - quite the opposite in fact, for the lab is dark and empty when we arrive, because it's midnight and there's nobody working. That, I think to myself, was pretty painless.

Above us, an alarm starts to wail and flash. After a minute, a squad of marines wearing helmets and body armour troop into the room and aim machine guns at us.

We raise our hands and surrender, as, thousands of miles away, Ed-C and Sam-C's lives begin, very subtly, to diverge from ours.

*

Interrogation is nightmarish, until the CIA guys arrive - Agents Mulheardy and White, whom we astound by recognizing and calling by name. They explain how the alternate us (us-C) are under observation for potentially world-threatening activities, and how our sudden appearance here while still being somehow under observation in England might have something to do with Ed-C's experiments. Mentally, Ed and I attempt to make sense of things. Now we are the alternate Ed and Sam. Now we have to continue the chain.

Witnessing it all again from the other set of eyes is plain eerie. We are so predictable. I find myself mentally finishing sentences for my counterpart.

It goes almost exactly the same as the previous time around. Disks change hands. Time-travel passwords are revealed. We hand over the electronic blueprints for the time machine, though Ed declines the offer to keep a copy, saying he's unlikely to bother building one of his own. We see our alternate selves off, headed back in time two days and another nanosecond.

There's one major thing we change, though. This time around, Ed's final piece of advice is different. "MARRY JEN."

Ed-C looks astounded, and never even reaches for the abort switch.

Afterwards, I'm infuriated with Ed, but also somehow unsurprised. Maybe he really does think his own life is just a plaything. Maybe he thought he was doing his other self a favour, or when it came to the crunch he just couldn't resist messing with the future.

In the end I say nothing to him, because there's nothing to say. Though we can never find out what happens to the other Ed and Sam, I hope they're okay.

*

As we take an overnight passenger flight home - no supersonic action this time around, alas - Ed checks his watch to see how much time we've lost altogether, and I try to pretend none of it ever happened, in preparation for resuming our lives where they left off, apparently, nearly three days ago. Between us, we decide not to adjust our birthdays to suit. It'd just be too hard to explain to our families.

The man sitting next to us is understandably curious when we start talking matter-of-factly about our temporal shenanigans. "Excuse me, have you two... travelled through time or something?" he asks.

"No," I answer. "We're actors in an upcoming time travel movie and we like to stay in character." The human mind is a wonderful thing. Implausible though it is, he's far more likely to swallow that explanation than the truth.

It's only when we finally reach Gatwick Airport and start looking for a coach home that a final thought strikes me.

"Where does the chain end?"

"It goes on forever," says Ed.

"But it can't go on forever. Even going back a nanosecond at a time, you eventually reach a time where the Kerrig Facility had never even been excavated. What then?"

Ed glances at me. "Are you sure you want to know?"

"Why do you say that?"

"I figured it out way back while Ed-A was explaining the theory of time travel to us. Frankly, it was the most worrying thing about the whole situation. Eventually, one of us dies. Possibly both."

I open my mouth, but can't say anything.

"You remember how I said that statistically, there are probably a few dozen of us who - just by chance - broke our legs stepping out of the time machine? Take it to its logical conclusion and someone is eventually going to get killed. The time machine makes a one-in-a-trillion malfunction and kills us both. You or I trip over and crack our heads open on the way to the interrogation room. The plane from England to America crashes and nobody survives. Actually, now that I think about it, the weakest link in the whole sequence of events between one iteration and the next is in the very first few seconds. Marines with guns. Somewhere, when you average out over a trillion iterations, one of a pair of us is almost certain to do or say something wrong, and they'll shoot us in response. In fact, four hundred and fifty billion iterations of that event without either of us getting killed is highly improbable. Maybe a few thousand would be more feasible, a million tops."

"So what about the disk? Somewhere back along the line, we lied? We made up the whole disk thing?"

"I'm sure we had our reasons, and frankly, there's no way we can ever find out for sure. There's no use agonizing over it, now. I daresay the alternate Eds will figure the lie out like I did. In retrospect, I guess we aren't to be trusted after all."

"Speak for yourself," I say meaningfully. "...I just wish there was a better way for it to end. Instead of an Ed and Sam a thousand universes removed from ours getting shot by accident."

"Who knows?" says Ed. "Maybe somewhere along the line, the two of us will decide to set up new lives in America instead. Working at that very facility, maybe. Again, we'll never know for sure."

"Time travel sucks," I declare.

"That it does, Sam," says Ed. "That it does. Right now I just want to go home and have a traditional post-adventure cup of tea."

"Maybe I'll call Jen over," I grin.

Ed groans, but he only has himself to blame.

Sort of.

Ed Rocks

"You reckon space is the final frontier?"

"Erm... define 'frontier'," replies Ed. It is a typical Ed response. Spin out the question a bit further, buy time to think of a proper answer.

"Well, there's nowhere else to explore, right?"

"Sheesh. Don't put it like that. That's like saying, 'Right! After hundreds of years of diligent exploration, we microscopic bacteria have carefully mapped every nook and cranny of our grain of sand. Lastly, we will explore the final frontier: every other grain of sand on the entire planet Earth.' As far as mankind is-- erm, as far as mankind and physical travel are concerned, space is the first frontier. The first meaningful one. Everything up to today is child's play.

"Other than that... well, I can name a half-dozen frontiers more final than space. Time, for one. Even the Kerrig machine didn't have the capacity to send a man more than two hundred hours back in time, and while we all know that 'true' time travel is impossible, there's still so much we don't know about the splitting phenomenon, divergent universes, and what occurs during transit... and what happens when you go forwards instead of backwards. Then there's the subatomic, that is to say superstrings. Then layers, once the scientific community finds them. Not to mention the as yet almost completely untouched depths of the human mind, and artificial intelligence, and the unexplorable depths of the Pacific and the Earth's core and Jupiter's atmosphere and the Sun's upper layers. All of these are places we will get to one day. And all of them will be a LOT harder to solve than the light speed problem."

"So I guess we won't be able to dive into the Sun in this thing," I say, climbing up the ladder and into the cockpit of the angularly-constructed, lorry-sized, vaguely hemispherical, antenna-spined hedgehog of a spaceship which is quietly exhausting water vapour from a vent on its back. It's powered by cold fusion, and has no obvious thruster exhausts; it doesn't need them. The ship's name, stencilled on the side, is apparently Ed Rocks.

Ed has been building the thing for about six months, though I'm almost positive he's been drawing up plans for it far longer than that. He built it entirely in the basement, though. I must remember to ask him about that.

"You know, it was the little things that were the hardest," he says, following me up the ladder. "Like programming the airlock safeties, and figuring out what to make the coolant pipes out of. And these." He flips open a panel on a nearby piece of external hull. I look inside, seeing wiring in seven or eight different colours.

"Circuitry access points?" I guess.

"No, the clippy thing on the panel that holds it shut. There are about five hundred of these all over the ship. They always look so simple until you try to design one yourself which isn't going to freeze solid in vacuum."

I climb through the ring airlock into a two-seater cockpit which resembles that of a commercial airliner in terms of space and number of switches. In the opposite direction, a cylindrical crawlspace apparently leads all the way down the spine of the ship, allowing access to all the systems, which are modular and multiply redundant. I can see at least a hundred panels featuring handles identical to the one Ed just showed me - they line the inside of the tunnel, in various shapes and sizes.

"So the engine was pretty easy by comparison?"

"The screw drive, as I call it, was a walk in the park," says Ed. "I'd had the design on the books for long enough anyway."

"Dare I ask how it works?"

"Basically it uses electricity to perform an extremely weird subquantum interaction which results in the drive reacting against the fabric of the universe itself."

"Doesn't that... you know, violate Newton's Third Law?"

"Not really. When we move forwards, the fabric of the universe moves backwards... a bit like a water paddle. But I reckoned screw drive - as in Archimedes' screw - sounded cooler than 'space paddle'."

"Well, coolness is what spaceflight is all about, right?"

"It is in my book. Anyway, the fact that the screw drive doesn't use rocketry means it doesn't have to be mounted externally - where, if it was damaged, I wouldn't be able to get to and fix it because I don't have a spacesuit. Yet. Instead, it's essentially built into the skeleton of the spaceship. The ship is lifted by its own frame. And if part of it gets damaged, the rest can keep operating." Ed shuts the airlock behind us and locks it. He motions for me to sit in one of the seats, and climbs into the other one.

"Erm, are we taking off now?"

"Why not?"

I glance upwards through the canopy. Up at the basement roof. "Well, how do you plan to move the house out of the way?"

"I guess I didn't tell you about the other drive, did I?" smirks Ed. "A reactionless drive is one thing, but interstellar travel at any sensible kind of speed in an Einsteinian universe of this size is quite another. The screw drive is for manoeuvring. This drive? 'S gonna take us to the stars."

"And how does this one work?"

Ed grins, and reaches for an exciting-looking button on the control panel. He flips up the transparent plastic lid which covers it. "Magic."

And suddenly we are four hundred million miles from home.

The First Frontier

"That's Jupiter," I gasp, seeing a huge orange and red bands which dominates the lower half of the scene outside the ship. We are floating over it.

"Yup."

"That's Jupiter! Instantaneous translocation? We got from Earth to here in... an eyeblink!"

"Magic," says Ed, checking over a large number of readings and gauges to make sure, among other, more terrible possibilities, that the ship isn't about to decompress around us. "Light can eat our dust," he adds.

"Why do you call it magic?"

"Clarke once said that sufficiently advanced technology is indistinguishable from magic. I figured the technology that just tunnelled us across thirty-six light minutes of vacuum was sufficiently advanced to be worthy of the name."

"So you can't tell me how it works?"

"No. But I can tell you its limitations, and they're worth knowing. Number one: conservation of momentum. We retain all our angular and linear momentum. If we're spinning before a jump we'll be spinning after it."

"Okay."

"Number two: conservation of potential energy. The gravitational potential difference between our start and end points is always zero. That means you can only jump between places where escape velocity is the same. That means we can jump from, say, a position on the Earth to one above Jupiter with ease, but not any point in between. If you figure out the equipotentials it also means you can't jump from the Earth's surface to ANYWHERE near the Moon... because the Moon, all of it, is too far out of the gravity well. And, if we wanted to visit the Sun, then we could do it now, but it wouldn't be a good idea... because we'd end up VERY low over its surface, and probably fry.

"Which is where the screw drive comes in. You notice we've got gravity in here?"

I blink, and do indeed. A steady one gee is still pulling me downwards in the same way that it has for my entire life. "Artificial gravity?"

Ed laughs once, sharply. "Artificial gravity? Well how about inventing antigravity as well while you're at it?" He roars with laughter. "Ehh, forget it, you weren't to know. To the best of my knowledge, which, granted, is incomplete, it's physically impossible to fake a graviton. The only way to get real gravity in here would be to plate the underside of the ship with neutronium, and quite frankly if you find someone with the technology to obtain and work neutronium, do give me his, her, or its phone number. We appear to have gravity in here because the screw drive in the ship skeleton is accelerating upwards and pulling the ship up with it at nine point eight one metres per second per second. We're heading out of Jupiter's gravity well. This control here? I can harden or soften our acceleration."

Ed makes sure I have my seat harness on and fiddles with the control a little, exposing me to highs of two and a half gees and lows of a worryingly upside-down minus one, with a moment of weightlessness in between. I try to stop myself feeling ill as we resume our ascendant trajectory.

"The screw drive is for manoeuvring in real space - raising and lowering the ship through gravity wells in between jumps, and also for docking and jazz. And finally, number three: point and shoot. To make a jump, you use this other control to aim the antenna at wherever it is you want to go. Draw a line across the universe in that direction. Sooner or later it'll intersect another part of space with the same gravitational potential as this one. We stop there. We aim at Jupiter, we stop at Jupiter. We aim at a star, we stop there. We miss the star by slightly too much - I'm not sure what happens."

"Just out of curiosity, do you have anything in here which is designed for real jazz?"

Ed turns on a piece of music which, after a while, I realise is Also Sprach Zarathustra. Groan. "Aww, come on, originality, dude."

We go through Blue Danube, the Imperial March theme, Martin Luther King's "I Have A Dream" speech and Aerosmith's "I Don't Want To Miss A Thing" before I persuade Ed to give a rest to his somewhat erratic audio library and put on some actual jazz.

"You know," says Ed, as we soar out of Jupiter's gravity well and admire the Spot, "in all of this universe's history there have probably been billions of cvilizations. And I'm sure at least a few million of those have made it into space and discovered magic. So for each civilization there's gonna be this one guy who first had the idea, and invented the magic drive. One guy for each civilization. And for humanity, that's me. I'm... I'm the first representative of humanity on the universal stage. Like, if you're gonna hold a council with one person from each civilization, and you say you're holding it at the centre of the galaxy, and it's first come, first served... then that's me. I mean... that's like the coolest thing ever. I mean... if the whole point of spaceflight is coolness, then that's it, mission accomplished and we can go home now, know what I mean?"

"Aren't there prizes you can claim for getting into space on a privately-owned spaceship?" I muse.

"Yeah, but I'll leave them. Somebody who actually put in some effort can have the cash. I have the unfair advantage of being a frickin' genius."

"This is true."

I've never found out where Ed's money actually comes from. He runs out of notes at the pub sometimes, but apart from that he never, ever worries about cash and always appears to have limitless resources on hand. He of all people does not need this money. My current theory is that he licenses out some insanely valuable industrial process for which he owns the patent.

"I wanna go to Andromeda," says Ed, rotating the ship to point towards an extraordinarily distant blob of light.

"We can't go to Andromeda," I remind him sternly.

"Well then I have a better idea."

Men Like Large Amounts Of Kinetic Energy

Something's very, very wrong. I don't need to hear Ed jump, swear, and scramble for the controls to know that. We were supposed to be jumping to Epsilon Eridani. I was expecting orange light to fall across us as we arrived in the εEri system at a relative speed small enough to make it appear that we were at a standstill.

Instead, my first instinct is to duck as a reddish star whizzes over my head at phenomenal speed.

Whizzes over my head?!

"ED! WHAT THE-" I begin, but he holds up a hand. Serious concentration is on his face. I've only seen that look a couple of times before, both times in extremely dire situations I think we're lucky to have escaped alive.

Stars - all reddish - are clustered ahead of us. They shoot past us like rockets. We're plunging headlong into the heart of a galaxy or something. We're gonna die. We're gonna hit one and die.

Ed finishes typing coordinates and slams a button. For a millionth of a second, scintillatingly bright yellow light and hideous amounts of radiation bathe the Ed Rocks - then, we are over Earth, and motionless.

There is a lengthy, shaky pause.

"We didn't get to Epsilon Eridani," says Ed.

"No kidding, MacPherson."

"We missed. Our trajectory line was off or something. We went past Epsilon Eridani and kept on going until we next intersected a gravitational field. Do you know how empty space is? Neither do I. Nor what happens when you miss your target. We could have circled the universe for ever for all I know. I've no idea what could have happened. It's just not something I investigated. The targeting antenna is the single most precise, fault-tolerant and infallible device I've ever constructed - it's capable of hitting our Sun accurately from anywhere in the observable universe. We were supposed to hit Epsilon Eridani and I thought there was no chance of error but it turns out there was.

"I think we ended up in what used to be a quasar."

A quasar. Quasars are astoundingly energetic galaxies of the order of tens of billions of light years away from Earth. Compare that with Epsilon Eridani, a mere eleven light years distant. Quasars exist on the observable limit of the universe and are so far away that they have been outlived by their own light. They no longer exist as quasars - in the aeons it took their light to reach us they have collapsed to ashes, the ashes have re-ignited and they have begun to shine again as "normal" galaxies.

Quasars are bright. Quasars are a long way away. Quasars are old. But there's one other thing - relative to our galaxy, all quasars are moving outwards, rushing away at significant and ever-increasing fractions of the speed of light. That's the expansion of the universe in action. That's the cause of red shift.

That also means that when a spaceship from our galaxy accidentally tunnels to a galaxy twenty billion light years away, while retaining all its original momentum, we arrive at anything up to ninety percent of light speed relative to that galaxy. We streak across their galaxy at insane speed - stars we see around us are relativistically distorted, clustered directly ahead of us and red-shifted as we move towards them. Ed scrambles for the controls, somehow manages to get a lock on our home galaxy, and gets us home as quickly as possible before we cannon into something hot or hard at relativistic speeds.

"We could have been killed," says Ed, after explaining this. "I don't know what caused the fault - it only happened once, because we were able to tunnel home. But I'm going to land and find out what caused it." He takes the controls and begins to move us into a steady descent.

"We can't jump straight back into the basement?"

"I don't want to risk it again, and besides, we're too high up. Equipotentials, boy. Equipotentials. Don't worry. I'll get to the bottom of this."

Nine Years

Ed took a week to figure it out.

"Epsilon Eridani does not exist."

"Excuse me?"

"How much have I told you about cosmology recently?"

"Not a lot."

"Right. This universe, our universe, is constructed in layers. A bit like a person in the Antarctic wearing a dozen different layers of clothing, a bit like a heavily insulated wire, a bit like a book of carpet samples. Each layer could in theory be considered the 'top' layer depending on what angle you look at it, each layer is intrinsically connected to the all the others to various extents, each layer affects the others to various extents, and each layer has different properties. There are seventy-nine layers in total."

"And you discovered this how?"

"Magic. So for example we live in one layer, and there's another layer 'above' this one which contains what I guess is best described as our layer's config file."

"I remember you telling me about that one."

"Yes. It was the first one I found. I've found more since then. Anyway, I found a hole in one of the layers."

I stare blankly. Ed taps a button on the nearest computer and a projector attached to the basement ceiling starts shining an image on one of the walls. The image is a render of a translucent sphere - it looks like a cross between a map of space, an onion, and an ultrasound image of an unborn infant. A tiny label at the centre of the rotating diagram marks Sol. Other stars in the stellar neighbourhood are also marked.

Epsilon Eridani, if it still existed, would be at the centre of a spherical chunk missing from one side of the sphere - like a stone removed from a mutant, lop-sided peach. Judging by the scale, there's no data - whatever the data happens to be - from anywhere within roughly half a light-year of Epsilon Eridani.

"A hole?"

"A spherical hole," said Ed. "As you might guess, light speed varies by layer. These readings come from analysis of a layer where light travels roughly a billion times faster than in ours. I checked again and got the same response back. There's nothing there, just a gap. I took readings from several more layers," he adds, pressing keys and cycling through several different, more alien-looking diagrams, all with the same black hole. "Same result every time. Every layer I investigated. Something has somehow punched a light-year-wide hole in the universe. When we tried to jump to Epsilon Eridani, which looks like it's still there because this event was less than eleven years ago, we just glanced off the outer edge of the hole in almost the opposite direction... and kept going almost forever.

"But there's a problem. The hole is getting bigger."

"How fast?"

"Light speed. Our light speed, one light year per year. Which means that sometime around the start of 2013, it'll reach Earth. And maybe destroy it."

"Maybe? You don't know?"

"No."

"...Can we stop it?"

"I don't know."

"Well, what is it? Do you even have an idea?"

"I... I don't know." Ed looks around at the white walls of the basement, looking at who knows what. Then he opens a drawer, pulls out a small pen-shaped object and pushes a button on it. It starts emitting loud white noise. Ed holds it up. "You know the CIA are always listening," he says over the noise; his voice is distorted, difficult to make out. "I don't mind that most of the time. But the concept of an energy virus is one I never want to leave this room. Can you imagine the consequences of... of implementing a... you know that Game Of Life thing? 2D grid of cells, ones and zeros, breeding or dying according to a tiny number of rules. Each part of our universe affects every other part of the universe according to rules: more complicated rules than the Game but rules, nevertheless. So, what if you could make a patterns, not at the cellular level, not even at the molecular or atomic level, what if you started writing ones and zeros on the quantum foam? What if you built a pattern that could reproduce, with or without matter, with or without vacuum? What would happen if it began reproducing? Can you imagine how fast it could reproduce, how fast it could expand? Could you stop it?"

"I don't know," I reply. I can barely hear my own voice.

"Nor do I," says Ed. "I've deliberately tried not to know. Never thought about it, never wrote down theories or equations or diagrams or even put the word 'energy' and the word 'virus' in the same paragraph. This isn't splitting the atom, this isn't antimatter refineries, this isn't even a nanotech grey goo nightmare, if this is possible, if this is what I think it is, then this thing could eventually consume the whole universe."

"You always said if it was possible to destroy the universe then somebody would have destroyed it by now."

Ed smiles without humour. "And I still don't know who exactly I was trying to convince. Anyway... it's just a theory. And we have about a decade to figure out what to do about it."

"Correction. We have a decade to figure out what to do about it, and then do it."

Ed turns off the white noise generator, and puts it away. "You're right. In fact, I've put it off for long enough. I think it might finally be time for me to call that conference."

Do Not Fire From Target Continuum

It's two months later, and the promised conference is on. It's a scientific conference, by the way. Not a press conference, though the press do seem to have started turning up.

I've heard at least one person suggest that the combined total IQ in this lecture hall is probably larger than in any other lecture hall ever, which sounds ridiculous - there are far larger lecture halls in the world - but I can't deny that there are more ridiculously intelligent people in this room than I've ever seen in one place.

This is the fifth of five days of lectures. I turned up for the first one but skipped the rest, after it became patently clear that Ed has only ever fed me distilled, baby-language versions of the things he's actually been quietly discovering in his basement for the last two and a half years. When you get down to it, Ed is a physicist, and while some physics does indeed involve firing excitingly small particles at each other at excitingly high speeds, rather a large amount of it is very hard mathematics, and here, in front of his peers, people he doesn't need to talk down to, Ed has cut loose. Suffice it to say, my tensor calculus is less than stellar. He lost me at "Hello".

Ed's findings are shaking the world.

He adds extra terms to equations which have been carved in stone for seventy-five years. Somebody challenges him, and he explains that the extra terms are necessary to explain certain phenomena he has observed. Nobody else in the world has ever seen these phenomena - everybody laughs sceptically. Then he wheels out some insane piece of engineering he built eighteen months ago and demonstrates it to them, right there in the hall. His new theory of the universe - layer theory, it's called - has hit headlines internationally. He seems to have drawn a line under all our current knowledge and started a fresh piece of paper. Time travel, FTL travel, direct mass-energy conversion, teleportation, all that stuff which would be so great if it really existed, all that stuff which is the very meat and drink of pulp science fiction but frankly looks more impossible the more you study it - it's like the curve just dipped so far into the impossible that it wrapped around at infinity and came back from above.

It seems a lot of people suspected a change was coming. There's a delegation of American scientists who have apparently been picking away at the teleportation problem for several years. The alien invasions proved FTL to be possible. The Sun going out for five seconds proved that if nothing else, it was possible to turn off the Sun for five seconds, though to the best of my knowledge only a couple of intelligence agencies actually linked that to Ed. But nobody expected this much new material in one go. Nobody expected working lab demonstrations and exhaustive experimental data to back it up. And certainly nobody expected it all to come from the same lone, unknown college student. It would be wrong to say that Ed is a well-known scientist. Most people don't know he exists. His actual name has only been mentioned in the news once, and that was over two years ago, the start of the giant robot era. The rest of his experiments have been kept pretty quiet. Ed is a total nobody, and some people find this almost insulting. Who the hell is this guy? This kid? What is he, a robot from the future? Where is getting all this data and technology from? How does he know all this?

Lately, I've been pondering that question myself.

"Let me cover a bit of history for you. Just over two years ago, planet Earth was invaded by aliens from another planet. Even now, it's still hard to believe that it happened and harder still for me to get up here and say so with a straight face, but it is an undeniable fact. Various major cities were attacked by swarms of what were later identified as unmanned craft controlled by sophisticated though non-sentient artificial intelligences.

"We got lucky. A short time previously, I had finished constructing a directed electromagnetic pulse weapon. Tuned correctly, this could be used to shut down the AIs running the ships, causing them to self-destruct - a mechanism military experts concluded had been installed to prevent our gaining access to the ships' weapons and FTL technology. We deployed DEMP weapons worldwide, and beat back the aliens. Life went on.

"A month later, the aliens came back. We quickly discovered to our cost that the craft were now shielded from DEMP attacks. Fortunately by that point we had a new secret weapon - a heavily-armoured, railgun-armed fifty-foot robot. The prototype was blown up pretty swiftly, but the designs were rapidly rushed into mass-production in time for a large number of volunteers around the world to pilot them remotely against the invaders. The aliens were once again beaten back. It was during this conflict that a formal Space Defence Coalition was first set up. Once the aliens had been repelled, two hundred of these giant robots were posted all over the world, with volunteers including myself on call day and night to defend the planet if the attackers ever returned. In January of last year, they did: a sporadic series of increasingly aggressive kamikaze attacks, with bomb-laden drones dive-bombing major cities from space. For six months we successfully held these off on almost a daily basis. The last such attack was June 24th of last year. Then, suddenly, they stopped.

"SDC analysts concluded that these aliens, whoever they were, were planning a larger attack, or perhaps working on a new, more powerful weapon to use against us. The Coalition has remained on high alert until a few days ago when the alert level was at last stepped down to nominal. This is why I called you all here today. This is what I arranged this conference in order to announce to the world."

Behind Ed, projected across the screen above him, the blue onion-skin diagram he showed me several months ago appears. The hole is fractionally bigger now, not that I'd notice unless I was looking for the change.

"Until today there was a lot we didn't know. We didn't know who the aliens were. We didn't know what they wanted, or even what they looked like. We still don't. But we do know where they come from. The aliens are from Epsilon Eridani, and the weapon they were working on is called an energy virus."

That's Your Solution To Everything

Ed is now explaining to the world what an energy virus is. This is not a step he is taking lightly. We turned it over for a long while before deciding there really wasn't any choice. Even so, he is describing it in the vaguest possible terms, at the same time underlining the fact that to attempt to engineer an energy virus of our own would be to flirt with sudden and complete human extinction. We hope the world will get the message, though I suppose we'll never know if they don't...

"As near as we can tell, the energy virus was triggered some time during the day of June 25, 2002. The 'explosion' if it can so be called instantly wiped out the entire Eridanian race and destroyed the star Epsilon Eridani shortly afterwards. This is why the Eridanian attacks stopped. Assuming the vacuum decay zone continues to expand at light speed, the wavefront will reach and swallow up the Sun and the Earth on December 22, 2012. That gives us just under ten years in which to come up with a plan and carry it out."

Ed is speaking rhetorically. He already knows what we're going to do about it; I came up with the idea a few weeks ago. He humours a large number of people by letting them voice their ideas. No, there's no physical way to defend ourselves from the virus: even setting off an energy virus of our own would merely destroy our solar system a few years earlier. We can't run from it, the energy virus is going to swallow up the entire universe in time, it's as simple as that. More ideas are thrown around. People propose setting up organizations, think tanks, investigation programmes. Some people suggest there's no way we can save ourselves and we should live out our lives to the fullest, a suggestion I'm sure everybody in the hall has already contemplated momentarily. The debates get pretty heated. Several people are getting quite emotional.

It's several minutes later when somebody hesitantly raises his hand and says, "Earlier this week you mentioned that practical time travel seemed to be, uh, well, if not practical, at least possible. To some extent. Now, perhaps I'm misinterpreting these findings, I don't know, but couldn't we, um, go back in time, and go to Epsilon Eridani and prevent the energy virus ever being created?"

"Yes," says Ed. "Yes, we could." He spots a familiar individual preparing to protest and singles him out. "Doctor Qvenild?"

It's the bearded Norwegian, the head scientist from the Kerrig Facility. Qvenild is a nice guy, very smart, and though Ed and I only met him briefly I'm told Ed still trades information with him online now and then. Ed's spoken to him a lot more in the last few days, since he flew in for the conference. "The problem with that idea is that we can't just send one person backwards in time. All that would happen for us is that the individual sent back in time would disappear from our universe forever. He'd arrive in a totally different universe, split off from ours at his re-entry time. If you really wanted to save humanity like that, then I suppose one would have to gather every human being in the world together and send them all back in time at once."

"Quite right," says Ed. "And even disregarding the unimaginable logistical and political problems of gathering the entire population of the Earth into one place, one also has to consider that the place we arrived would be an Earth already fully populated. We'd instantly double the population of that Earth, with disastrous consequences. Taking every human being back in time at once is completely impractical. Next slide please?"

A murmur begins to circulate as everybody takes in what the next slide is an image of.

"We're going to have to take the Earth with us."

The slide shows the planet Earth, encircled with satellites. "My plan is to place about a hundred of these satellites in very low Earth orbit. Obviously the nice geometric arrangement shown here can't be maintained indefinitely, as the satellites must be in motion; the orbits will be calculated to line up like this at regular intervals. The satellites will contain machinery which will enable them to instantaneously project a skew field - sorry, a negative skew temporal field for those of you who weren't at that lecture, a skew field is what takes you backwards in time - over the entire planet Earth. They will also be provided with enough power to transport the entire planet backwards in time to a point before, hopefully substantially before, June 25, 2002.

"With accurate adjustment for relative 4-momentum and other completely bananas stuff like that, it should be a simple matter to calculate our re-entry point to be at the leading or trailing Trojan point of the Earth already present in the universe we arrive in. That will place us in a stable orbit. From there we will not only be able to communicate with the other Earth, whose inhabitants will be astoundingly surprised to see us, but also send an expedition to Epsilon Eridani to find and make contact with their inhabitants, and hopefully make peace, or at least stop them from developing the energy virus. How early we arrive will be a factor here; I hope we can generate enough power to arrive before the Eridanian conflict even begins, but that will depend on how many years it takes us to construct and activate the the net of skew satellites, because the number of years we can travel backwards in time will be strictly limited by the power we can supply to those satellites.

"Anyway, that's the plan, and now you know why I called this conference. I need help. I can't do all this on my own. Right now this diagram is all the plan I have. I need every space agency in the world to drop what they're doing and help. I will give you information, and technology, and knock prototypes together, but I'm not organized. I need people who know how to coordinate things, managers, people who are organized. People with power, contacts, resources, brains, and billions of dollars. Yes, a lot of money will be involved here. It's that or complete extinction. There it is. There is our threat, and there is our solution. We have ten years to implement it.

"Any questions?"

Your Radical Ideas

"I don't have time for pleasantries, Sam. Earth is going to be wiped out in eighty-five minutes."

Hearing this on the phone one morning at work is surprising for two reasons. Firstly, last time I checked, we still had well over four years until the Eridanian energy virus shockwave reached us.

Secondly, I haven't spoken to Ed in a very long time. We were in our final year of college when he found the energy virus. I carried on with my course, finished it, got a degree, got an office job in the city. But Ed just dropped right out. He moved to America, and started working for NASA on Chrononet, which is the (in my opinion, ridiculous) name that was eventually given to the proposed satellite network that will ultimately be used to drag the entire Earth ten years backwards in time. I kept in contact with him for a while but eventually communication just slid to a halt. I personally haven't been involved in a potentially Earth-destroying hijink since I left college. Which I guess means I'm due.

"Ed, what did you do?" I ask wearily, wondering why he needs me of all people. Judging by the many voices I can hear rumbling in the background, he is in a room filled with smart NASA technicians.

"It wasn't me this time. It's an asteroid. It's a fifteen on the Palermo scale."

"Ed, the Palermo scale only goes up to ten."

"No. You're thinking of the Torino scale. The Palermo scale is logarithmic and goes up to infinity."

I boggle. "You're saying this thing ranks at level fifteen on a logarithmic scale?"

"It's moving at a tenth of light speed. It came almost directly out of the Sun which is why we didn't see it until about five minutes ago. We're still taking readings on its size..."

"Nothing in the universe moves that fast naturally!"

"Yes, yes, I know, we'll ponder that question after we stop it hitting Earth. And you're about to ask me how we do that. And the answer is I don't know. Any ideas?"

Brilliant.

"What defences do we have already in place?"

"The asteroid was picked up about two minutes ago by a ground-based long-range warning system which was set up after we insisted it was going to be necessary to protect the Chrononet satellites. But that thing is designed to spot small chunks of matter, and certainly not deflect them - standard practice was going to be to move any endangered satellites out of the way via retro rockets. We can't very well move the whole Earth."

"Can't we?" I ask in all seriousness.

There's a brief pause while Ed rapidly turns the concept over in his head. "No," he replies. "Absolutely impossible. Keep thinking."

"Then what do we have?"

"Basically nothing."

"Can we build a rocket, fire it into space? Can we convert an ICBM in time?"

"No. And ICBMs are too slow. By the time it hit, the asteroid would be less than a second from impact. Our fate would be sealed by that point."

"What about your projects?" I ask. "Have you built anything new in the last four years?"

"I've been pretty busy with this accursed satellite project," says Ed bitterly, confirming the increasingly unsettling rumours that work on the Chrononet satellite design has been proceeding with almost glacial slowness, "so, no. But we do still have the back catalogue. I just need to know what to do with them. I know you wrote this stuff down, dig out your list and go through it, there must be something we can use."

I don't have access to my list - it's on my home computer, and I'm at work - so I resort to my own, fallible memory. "Giant robots? Are they spaceworthy?"

"Yes, but we could smash all two hundred of them at maximum acceleration into this rock and not deflect it an arcsecond. We could divert it given an extended push, but there is absolutely no way of rendezvousing with something moving at that speed. They could still be used as a delivery system, but a delivery system for what?"

"The fusion inhibitor. The computer virus which controls people's brains through monitor static."

"Both useless."

"Layer theory. No useful applications of layer theory we could use?"

"Nothing that would take less than a week to put together."

"Bread-slicing wormhole?"

Ed is silent.

"Ed?"

Then I can hear him shouting to other people in the room, "Okay everybody, listen! A plan is being formulated! I need Tyro woken up and active at my terminal, and I don't care how many federal laws you have to break to do it! Get SDC Response in the loop, get every pilot woken up and every mech they have in the air! I also need somebody to go-"

"Wait, that wormhole was three feet wide! How big is this asteroid?"

"It's a seventeen hundred metre sphere," says another, unidentified voice. It's at this point that I slowly begin to realise that while Ed has been the only person talking so far, I am in fact on the phone with something like a hundred and forty people. As best I can tell in the ensuing noise, several of them are already raising objections about waking up whoever this Tyro person is.

"We can deal with that," says Ed. "I've got a plan. Don't hang up." There's a short pause while he apparently gets the attention of everybody in the control room he's in, and then, over the following five minutes, he explains his plan. His ridiculous, insane plan.

It involves me to a rather distressing extent.

My Other Car Is A Giant Robot

There are roughly two hundred mechs - part of an international Space Defence Coalition - posted around the world. They are arranged roughly evenly, though there's some clustering around more densely populated areas, which have proved to be more popular targets for Eridanian attacks. The United Kingdom is defended by two of these. There are five to ten pilots taking shifts at being on call to pilot these at a moment's notice - until Ed went to America he was among them. One pilot, named Marcus, was activated a few minutes ago and instructed to fly his mech to here, to the market square near where I work, as fast as possible. Meanwhile I made my excuses at work and came here, where I've been waiting for only about a minute total.

"As fast as possible" could use clarification. Ed released a whole bundle of new technologies to the public back when he announced the energy virus's existence, and while it's taking an agonizing amount of time for practical implementations of these technologies to filter through to the general public, the SDC have had the means and motivation to basically pounce on them. Consequently the basic mech design has been upgraded considerably in the past few years. For example, it used to be powered by jets, rockets and thrusters: that is to say hot, dangerous flames. The new design doesn't have that, it has a version of Ed's reactionless screw drive - or "liftweave" as the marketing types seem to be calling it now - woven into its superstructure instead. Screw drives are actually insanely dangerous devices in that, supplied with enough power, there is no theoretical upper limit to the level of acceleration they can provide. So, without overrides forcing acceleration to stay within a certain tolerance, it would become very easy for a pilot to ramp up to twenty or more gees and simply crush himself to a pulp. This in turn means that even though the robots themselves aren't what you'd describe as aerodynamic, they are quite capable of breaking the sound barrier at sea level.

Technically it is illegal to break the sound barrier over land, and as the sonic boom echoes distantly over the market square I consider it to be highly doubtful anybody managed to get special permission before Marcus' mech launched. He probably did a lot of damage en route. He'll probably do even more on the next leg of his journey. Hey ho. Price of saving the world.

Almost everybody in the square scatters in alarm as the mech draws to a halt over the square, and gently comes in to land, all in almost eerie silence. These days, a mech is just another piece of military hardware like a tank, but it's still pretty unusual for the average member of the public to see one in action, so many remain (foolishly, really) at the edge of the square, waiting to see what will happen next. Some take photos.

From the mech's external speakers boom the words: "Sam Hughes?"

I run over to stand in front of the huge thing, and wave. "Yo," I shout back at it.

There's a momentary pause, and then the mech folds down, until its torso is at ground level. Panels of armour move apart to provide access to the cockpit. It's empty. Of course. To pick up the pilot en route would waste time - he'll be flying it remotely. I climb inside.

The cockpit hasn't changed much from the prototype that Ed and I designed. The seat is a huge, whole-body-enveloping acceleration couch with armrests and heavy restraints all over. There's a big LCD screen - curved, a full one-eighty degrees wide - which relays a composite image from the mech's many external monitor cameras. At the bottom of the seat is an array of foot pedals, and at the end of the armrests are... an unfamiliar set of controls.

These are new. I've heard about this kind of interface before, but never seen a real one, though you can buy them for your computer if you have enough cash. Replacing the old-school keyboard and mouse, there are now five tiny blobs at the end of each armrest, into which I can slide my fingers. They are attached to the armrests but only magnetically - and there are sensors around the cockpit which can detect their positions in space, meaning I can make essentially any gesture I like with my fingers and hands, and the machine will be able to interpret it as a movement or some other instruction. Very clever. I haven't a clue how to work them, of course.

It seems I won't need to: Marcus' image flicks up on the main screen. He is in his late thirties, and the image looks like its being relayed from a webcam in his house. From what I can see he is wearing an identical set of finger controls. "Where are we going?" he asks. He hasn't had the whole plan - or indeed any of it - explained to him yet. Time has been very short.

I give him the address of the student house where Ed and I stayed during college. He tells me to hold tight, and my stomach drops away underneath me, as the mech leaps about a mile into the air. Marcus' chosen route is direct, but takes us a fair distance up in the air, partly to limit the damage caused by the sonic boom and partly because air resistance decreases at higher altitudes.

The mech levels out into a counter-intuitive upside-down Superman sort of posture - aerodynamic, and also leaving me on my back, in relative comfort, as opposed to face-down, hanging out of the seat for the entire journey. I relax very slightly.

Marcus sets up a flight path in the approximate right direction, then I help him find some map data on the internet that he can use to navigate to the right address. That takes a few minutes. Once the course is laid in, he asks what's going on.

"There's an asteroid coming towards Earth. It's going to hit central India in... an hour and ten minutes. You and I are part of the plan to stop it. Do you know what a wormhole is?"

"Yeah. I think so."

"Right now there are some people in America building a ring wormhole big enough to capture the asteroid. Once they're done, we're going to build a second one in India. Then we connect them up. We'll intercept the asteroid before it hits Earth, diverting it through the wormhole: passing from one side of the Earth to the other without ever hitting it. That's it. Pretty simple, eh? Only problem is, the asteroid is one point seven kilometres wide. Which means to stand a good chance of catching it, our wormhole is going to have to be about three kilometres wide. And the question of how you build a ring of metal the size of Gibraltar in less than seventy minutes is a very good one indeed. We're on our way to collect some of the equipment we need to build it, though to be honest, I don't know where any of the necessary raw materials are going to come from..."

"Is this wormhole thing gonna be heavy?"

"It'll probably weigh... uh, upwards of a hundred tonnes, I'm guessing. Why?"

"How strong is it?"

"Pass."

"Well, what's it made of?"

"Um... metal? You know, right now, I honestly don't know. It depends. Like I say, last time I checked we hadn't solved the raw materials problem yet. Why do you ask?"

"This mech is strong enough to lift a hundred tonnes, but that's about the upper limit. And if the ring is too weak, it'll snap when I try to lift it anyway. We're gonna need more than one mech to do this."

"That's not a problem. It'll have liftweave running all around it - it should be totally mobile on its own. Anyway, we're going to- we're here? Already?" I take a look down in utter amazement and see that Marcus is right - the road we're descending on is the one where my old student house is. Fifty miles in something less than ten minutes. Staggering.

The mech lands with a dull crunch, putting a sizeable dent in the road underneath it. The mech's shoulders are narrower than the two-lane road, so Marcus has little difficulty guiding it down to the right house. It folds down and I jump out, and ignore the large numbers of people peering curiously out of windows as I run up to my old home and ring the doorbell. As I wait for somebody to answer, I wonder what in the world I'm going to say.

"Hello?" asks the bespectacled female student who answers the door, staring in surprise at the fifty-foot robot behind me.

"Hi, you don't know me, my name's Sam, I used to live in this house when I was a student here. Um. When he moved out, my housemate Ed left some stuff in your basement, and needs it back urgently, so I came to pick it up. Is there any chance I could nip into your basement and get it? I swear I'll be in and out in less than a minute."

"We don't have a basement," she replies.

"Ah, you do. Trust me."

Mechcourier

It takes me a few minutes to talk my way in. Then we have to move some furniture and a rug to expose the basement trapdoor.

It hasn't been opened in a few years. There's a lot of dust around the place, though not too many cobwebs. All things considered, Ed left the place remarkably tidy. He took about half of his old equipment with him to America, along with all his data, stored on his unimaginably fast computer. The stuff he left behind is heavier, less useful junk. A regular computer, probably operational but hopelessly obsolete by this point. Six or seven dull-looking devices, each designed to interface remotely with a unique particle accelerator somewhere in the world... something Ed doesn't do anymore. There's a miniature gyro stabiliser, unusual in that I built it, not Ed - still, as far as I know, an integral part of every Hughes-MacPherson J8 Bipedal Armoured Mechanoid. There are other bits of electronic equipment scattered around the various workbenches. Pieces of curved metal, a few model spaceships... a bundle of screwdrivers and less readily identifiable tools, an old projector bolted to the ceiling...

I open up one of the metal cabinets under a workbench and lift a few spindles of blank DVDs onto the floor. Then I reach further in and pull out a red plastic ring, one metre across. And a remote control.

"Superb."

The girl who let me in is watching from the steps as I yank the keyboard and mouse out of the old computer. I put the mouse and remote in my pockets, and bound back up the steps with the keyboard in one hand and ring in the other. "Got what I needed, thanks," I say as I pass her.

"What is that?" she asks.

I'm already at the door. "It's a very long story."

"It looks like a hula hoop." she asks.

"Well spotted, it's not," I shout over my shoulder while walking back out to the mech. "I don't have time to explain and you probably wouldn't believe me anyway. Watch it on the news tomorrow morning, like everyone else. Marcus, you there? I need to put this ring over one of the mech's fingers. We need to carry it externally since it doesn't have an airlock."

The mech holds a hand out and I am able to slip the ring over its left index finger before climbing back into the cockpit. I take a last look back. The girl has followed me out. "What's going on?" she shouts. There's no point in answering, so I don't.

"I just got sent some coordinates from SDC Response," says Marcus as the mech folds back together again. "Apparently this is where we have to go next. Thing is, this is about a thousand miles above central India. Is that right?"

"Yup," I say. "We can't put the ring on Earth, the backlash from an asteroid tearing through atmosphere at point one c would be too damaging in itself. We're going to build it in space, it's the only way."

Marcus begins flexing his fingers, and the mech begins to rise. "Do we want to arrive stationary at these coordinates?"

"Yes, geostationary, please, and zero vertical component; we'll be maintaining constant altitude manually so there's no chance of falling into atmo while we wait. And preferably within half an hour so we have time for the construction."

"Right. At two gees with a turnover halfway I can get you there in good time. Two gees is a little heavier than you're used to but you should be fine in that seat. Are you strapped in?"

"Pretty much," I say, and I find myself squashed down into my seat as the mech begins accelerate southeast, rapidly gaining altitude.

*

"Sam," buzzes a voice in my ear as we tear over France.

"Ed. What's happening? Don't you have a program to write?"

"No, I've got Tyro doing that."

"Who's Tyro?"

"Oh, that's right. You don't know. Tyro is the AI that spawned from my propositional logic calculator back in 2000."

"You let it loose? Dude, I thought it was quarantined!"

"I know, I know, federal laws, men in dark glasses, I don't care, Sam. Tyro is a genius if you give him enough processing power to work with - which we have - and there's no way I could write a flawless UC program on my own in this little time. I had no choice in the matter and I'm not honestly worried about tribunals or whatever. Besides, Tyro is totally benevolent, as you well know."

"Well... if you say so. So... what's up? I assume you're not just calling to chat."

"Given that all the necessary cogs are now in motion I have a free moment to talk. You said it yourself, Sam: no way in hell does a rock move that fast, on that flat a trajectory, directly out of the Sun so we can't see it and directly towards the most populous location on Earth, by chance. No way. Somebody threw it at us."

"The Eridanians?"

"Maybe. Maybe not. I find it hard to believe anybody survived the energy virus when it first went off."

"They could have been posted in another solar system at the time. Maybe ours."

"Doesn't matter. The fact remains. Somebody up there wants us all dead. If they discover what we're trying to do, chances are they'll try to stop it. I think the ring is probably going to come under attack. That's why half of the world's mechs are going to be meeting you at the rendezvous point and the other half are coming to where I am. You have to defend the ring, before, during and after construction."

"Me? Can't Marcus do it remotely?"

"Well, he should be doing it, he's listening in. Aren't you?"

"Yup," says Marcus.

"I'm just saying, is all. Be ready. You might end up getting thrown about a bit."

"See, this is why I never joined the SDC, you know. The whole risking death thing. We should never have built this accursed giant robot in the first place."

"Aww, come on. Without us, the world would've been destroyed or enslaved half a dozen times over by now. Relax, forty-five minutes and it's all over."

Final Approach

Turnover is a little dizzying, but bearable and brief. By this time the mech is well out of the Earth's atmosphere, and still rising. Below me - below in a gravitational sense, from my point of view it's in front, because that's where my screen is - the Mediterranean Sea is ending, and the Arabian Peninsula beginning.

Looking ahead the picture is more complicated. The mech's tactical software is overlaying the picture from ahead of the mech with a number of symbols. Tiny green crosshairs indicate other mechs rising from their various bases towards the blue point in space which is the rendezvous point - where the wormhole is going to be built.

On the Earth's surface below, a pale red crosshair marks the point in central India where the asteroid is going to hit. The rendezvous point is connected to it by a straight grey strand, thin as spider silk. In the opposite direction, the strand extends off towards the Sun - a yellow glow, masked by software routines - and a deeper, more malevolent red marker which is the current location of the asteroid itself. Beside it, a tiny timer ticks down. Forty-two minutes.

This is a pretty sophistimacated piece of tactical software, I think to myself. The original mech just had a heat detector. Anything hot was flagged as hostile and had a range marker, and that was it. Laughably primitive, really.

"Chrononet is dying, Sam," says Ed, making me jump. I hadn't realised he was still there.

There's a machine in Edinburgh, a layer sonar, which, every five seconds, emits a pulse into one of the layers where c is a billion or so times higher than in ours, and records the time taken for it to echo back off the wavefront. There's a website where you can watch the second-by-second countdown and even listen, live, to the individual pings. The pings have taken an almost iconic status, something like the Doomsday Clock. And every day they get very slightly faster. Since the energy virus' existence was first announced the period between pings has halved. But that's not the part people find scary. The scary part is the lack of positive news about Chrononet, which has been steadily dropping behind schedule for over a year now. The scary part is listening to the energy virus approaching and worrying that by the time Humanity gets its act together it will be much too late.

But up until now, I haven't been scared, because I know who Ed is - the smartest person I've ever heard of - and I have confidence in him. So when he says something like "Chrononet is dying" my world is suddenly shaken. "Dying?"

"The problem is power. The amount of power that's going to be needed to flick such a huge mass so far back in time is orders of magnitude larger than anything we can currently generate, even in nuclear explosions. And until I can devise a power source, we can't design satellites, and until we design the satellite we can't construct launch vehicles and plan launches. We've got nothing."

"You always come up with something."

"I know I always come up with something. Whenever I've been building something in the past and I got stuck, it's like the answers were always there. They came to me if I just devoted some thought to them, you know? It used to be easy. But now the answers are all gone. I hit this problem less than ten minutes after you suggested the Chrononet solution, and it's now four and a half years later and I STILL don't have the faintest idea how to begin solving it. Nobody on the team does, and there are some incredibly intelligent people working with me. But here's the thing. Somebody does have the answer."

"To fling a rock that fast..."

"Yes. We need their power source. I don't care what you have to do. When the ring is attacked, as I'm sure it will be, you'll probably have a chance to make contact. When you get that chance, give me and an alert and we'll connect Tyro up to that communications channel. Tyro should be smart enough to decipher their language and start bargaining. Once you've offered our unconditional surrender, find out what they want and whatever it is, give it to them. Understand?"

"Perfectly, although if I'd known what I was getting into I wouldn't have climbed back into the driver's seat after giving Marcus the ring."

"That was your decision. But just try to make the best of it. Well... according to my instruments, you're at the rendezvous spot, correct?"

"So it would seem," I reply, as the sudden cessation of deceleration jolts me out of my seat against the straps momentarily. Then a faint downward gravity takes over, pulling me distantly towards the Earth, as the mech stands on air; or rather, nothing. Green crosshairs marking other mechs are now all around me like flies - I can see some of the mechs properly, though others are kilometres away, still too small to see. The blue rendezvous marker is large on my screen now. "Where are you?"

"Mobile control at Jacksonville cargo docks. It's a port on the Floridian east coast. Though 'mobile control' is just a romantic way of saying it's me and my laptop and a phone and a wireless network connection back to SDC Response. We've just finished building the first wormhole."

"Jeesh, that was quick."

"Give me a few minutes to get it on its way out of atmo and we'll start building yours."

"All right. Marcus, you still there?"

"Yeah, I know what to do," he says. The mech shifts slightly, and very gently pulls the red ring off its finger. Then it holds the ring out in front of it, pointing from left to right. I pray that Marcus doesn't drop it. We could catch it, but it would waste precious time...

Seconds tick by.

And then I can hear Ed shouting to various people around him: "All right! Ladies and gentlemen, we are moving on to phase two! The green ring you see in front of you is a miniature wormhole! We are about to connect it to another ring which is currently situated in cold vacuum! Unless you are piloting a mech, stay outside a fifty-metre radius of the ring if you want to avoid being sucked out into deep space! If you are piloting a mech, that radius is ten metres but be careful! Are we all ready?"

There's a chorus of affirmatives which I cheerfully join in, fishing the remote control out of my pocket.

"All right! Activating the wormholes!"

I hit the button for my red wormhole. Thousands of miles away, Ed hits the button for his green wormhole. Somewhere in some mystical alternate layer of the universe, the two wormholes connect, and Floridian atmosphere begins to vent out of the ring in front of me, sparkling slightly as its water content condenses and then freezes. A few seconds elapse. And then vwhoooosh, a thick grey/blue/black tube of material shoots out of the ring too, like an unlimited supply of playdough being extruded - nearly as thick as the red hoop is wide, growing at maybe twenty or thirty miles per hour, shooting away to my left where a pair of mechs have now grabbed the end and are pulling it steadily away and around in a gigantic circle.

Cosmic Shotgun

The revelation that Ed has a universal constructor is not one which should have surprised me back when he was explaining the plan at that lightning-fast briefing. The stuff he's built in the past, out of plain old raw materials like scrap metal and wood and glass, would, if we're being honest, have required warehouses full of highly specialised machinery to create. I never devoted a huge amount of thought to the problem, just assuming the apparent magic he was working down there was due to his towering intellect like everything else, but in retrospect I should have been more curious.

I guess he has his reasons for never explicitly telling me about the UC though. Like so many of his inventions, a universal constructor is one of those devices which is dangerous if you just tell people it exists.

Still, even with this deus ex machina of an engineering solution in our posession, contructing a pair of giant wormholes would obviously require two more things - lots of electricity (though no more than we already have access to) and...

"So, Ed. I never got around to asking you. What exactly are you building this wormhole out of? Where are you getting the raw materials from?"

"The UC I first made is actually pretty small - much too small for our purposes. So while I was constructing the green wormhole from the program I wrote way back when, I had Tyro coding up a larger version, a big black thing with a hopper which is currently sitting here at the port. We're at the port because this is a good place to find all the raw materials we need: metal, plastic, water for hydrogen and oxygen, copper, silicon. Basically anything is usable... The mechs are stripping the place down and hurling it into the hopper as fast as they can. It's all they can do to keep up, to be honest. Then the formatted output is fed directly through the green wormhole and straight to you."

"You reckon we'll complete it in time?"

"Unquestionably," says Ed. "With enough spare time for a cup of coffee, no less. Defending it when it's built is the hard part."

"You really think it's going to come under attack?"

"Any minute now."

I close the channel and wait nervously, listening to the dim humming noise of the wormhole growing past me and the buzzing of mechs patrolling around.

A thought occurs.

"Marcus, how come I can hear this wormhole growing past me and mechs buzzing around, in deep space?"

"Ah. That's a new tactical plugin. It takes the feed from your sensor inputs and interprets them into three-dimensional surround sound effects. Aural cues are extremely important in a combat situation, but the mech's armour is essentially sound-proof, and even given the external microphones, there's a limit to how useful actual sounds can be in combat, especially in space. Whereas with this plugin, you can hear things coming - even supersonic planes and rockets, and even in space. The plugin's a very simple software algorithm, not hugely intelligent, it's anybody's guess how it'll interpret some events, but it knows to go 'boom' when there's an explosion and 'whoosh' when something whizzes past you at high speed. The Coalition is hoping to turn it into something really sophisticated, though, something a trained pilot can use to almost fight a battle by ear. Or at least augment the usual readouts and alarms and things."

"It seems to be working pretty well."

"Well, beware of screeches, it screeches sometimes."

Minutes pass, and continue to pass. After a short while I dig out the keyboard and mouse I pinched from Ed's basement what seems like an eternity ago. I plug them into the still-operational ports in my seat's arms and get Marcus to temporarily give me control over the mech. It's a LONG time since I flew but it's surprising how it all comes back - I find myself unable to recall the key combinations for certain manoeuvres, then instantly tapping them out without even thinking a few seconds later.

A faint but growing bleep almost gives me a heart attack until I realise that it's the front end of the wormhole, come full circle. People controlling the other mechs - which are all unmanned - exchange instructions with Ed, and the tail end emerges from the red wormhole, which then shuts off. There are more exchanges, and four mechs drag the two ends together where they connect neatly.

Further graphics appear on my screen, added by some unknown force, perhaps Tyro: a translucent red cylinder which marks the projected path of the asteroid and a deep blue ring for the edge of the wormhole, which is much too thin to make out for real at the far edge. The latter widely encircles the former, which plunges down towards India far below me, needle-fine at the endpoint.

From above, where I now carefully take my mech, the wormhole is just a blue curve across space - from the right angle, a curve across the face of the Earth itself. For a second I can take in this dazzling view, then the Earth completely disappears and is replaced by empty space, for the two large wormholes have now also been connected.

With care I pass my mech through the ring - being two-way, it's far safer than the bread-slicer of yore. Then, on the far side, I turn around and see the other side of the world.

This wormhole isn't diametrically opposite the Indian impact point, as it doesn't need to be. Instead it's low over North America. The view, bluntly, is spectacular.

A minute or two passes, and I loop around the edge of the second wormhole and pass through again, emerging on the far side of the first, nearly back where I started.

"It's working," I radio to Ed, knowing several people have most likely verified this to him already.

"Splendid," he replies.

As the countdown drags on past the five minute mark, I ponder the form that the attack will take. Space battle is a difficult thing to figure out from first principles. What would work in space? Assume they know what they're dealing with and choose something which would be most effective against what we have. Any given mech is shielded against jamming and electromagnetic interference - plus it can receive encrypted remote commands on a thousand different frequencies, meaning remote hijacking isn't an option. Nukes aren't very effective in space. Missiles can accelerate basically without limit in vacuum, but can be trumped with a well-targeted railgun slug... What beats a railgun slug?

Anything?

"Ed, is—" I begin, but am interrupted by a monumentally loud and unpleasant noise - a thousand simultaneous but finely distinguishable horrendous screeches, each blazing its own meticulously plotted 3D path diagonally through the audio environment of my cockpit. I glance at the radar and catch sight of a rapidly fading orange-red trail for each noise - rapidly fading after shooting through local space at six nines of c. A jolt and a sudden onset of acceleration signals that Marcus has resumed control of my mech. Mech pilot chatter, mostly profane, explodes around me. I can hear weapons powering up - both real sound transmitted through the armour on my mech's limbs and simulated noise based on detected energy signature changes in the other mechs. Railgun slugs, somebody shouts, they were railgun slugs, high energy.

A fragment of wormhole pinwheels across my field of vision.

And The Rock Cried Out, No Hiding Place

Chaos.

Coloured graphics whirl across my screen far too quickly for me to assimilate. Attack plans and codenames and screeches flood my ears. Mad acceleration pulls me in every direction. Are we dead? Are we going to be?

"Sam, this is Tyro," says an unfamiliar, measured voice, relegating all the other chatter to the background. "Don't panic. Everything is under control. Sorry for the bumpy ride, but you'll be thanking us later."

"Somebody just shot our wormhole to pieces!"

With infinite calm: "Yes. High-energy railgun slugs from somewhere behind the Moon. A squad of mechs is currently in pursuit, but it'll be over half an hour before they arrive. Fortunately, transit time for a slug at that speed is less than two subjective milliseconds, meaning they basically cannot be steered, so as long as we keep moving unpredictably we can keep you alive. We have a contingency plan regarding the destroyed wormhole. Ed began construction on a third one after finishing the second."

"A third wormhole?"

"A spare. It seemed a prudent move. Ed's given me access to its liftweave control circuits which means I can steer and control it much more skillfully than the mechs. Currently it's a growing two-kilometre tower over Jacksonville. In a few seconds' time I'm going to drop the entire thing vertically through the green ring. That will take less than thirty seconds. After that I'll use the liftweave in the wormhole to loop it into position and connect it up. That part should also take less than thirty seconds."

I glance at the clock. Time is flying. The constantly changing direction of flight is seriously making me ill; I try to tell myself the alternative is worse. "When are we planning to do all this? We have barely two minutes."

"We want to keep it as small a target as possible for as short a time as possible to minimise the risk - that means we begin the feed at seventy seconds. Even so there is still a risk."

Tyro's voice fades out and mech chatter fades back in. It sounds like everybody is simultaneously having his own conversation with Tyro.

"Sam?" says Ed in my ear.

"Still here," I gurgle, barely able to avoid throwing up.

"I'm reactivating the Ed Rocks."

"Why?"

"You know why," he says, and signs off as suddenly as he signed on.

Grim fear grips me. I see an instantaneous flash of a handful of equally undesirable possible futures. Ed is planning for damage control. Ed "never beaten" MacPherson.

"Okay, everybody, this is it," says Tyro. I notice dimly that my mech has once again taken the red ring off its finger - then the third and final wormhole explodes out of it, slowly at first but accelerating under unguessable gravitational forces, as my mech jolts and whirls safely away from it.

There's a ping as an unidentified object springs into existence in nearby space. It's the enemy, though the fifteen-millisecond battle is long over by the time I figure that out. I don't get a chance to see what the enemy ship looks like before it's blasted to shreds from a dozen different directions by the remaining defending mechs. But it apparently has enough time to loose a single shot.

"We have a confirmed kill," reports Tyro as my mech ceases to manoeuvre madly. "The enemy has been neutralised. However the red ring has been destroyed, leaving us with only three hundred metres of wormhole tubing. I'm forming what we have into as big a ring as possible. Ed, is there any way to expand the wormhole diameter wider than the rim itself?"

Ed responds with a string of syllables which would be incomprehensible even if I could hear them clearly. "But if that works it'll be a miracle," he adds. It sounds like there are people around him. He could be anywhere.

The coil of incomplete wormhole ahead of me flexes and writhes and curls into a circle as it floats towards the white line which marks the predicted centre of the asteroid's path. From my vantage point it looks like a pitiful effort. Tyro announces a test power-up. My mech's sensors pick up the building energy inside the wormhole. There's a flash of ultra-violet. Then it falls apart, split finely into two separate rings, both also rapidly fragmenting into pieces.

I've seen too many movies to give up now. I can hardly hear myself shouting at Ed for ideas, guidance, inspiration. It's some time before I realise that what he's shouting back at me is "There's no time, Sam, we're out of time! For heaven's sake, look down!"

"We still have—" and I glance at the clock again just at the instant it ticks to zero.

The noise of the asteroid hammering past me - seventeen hundred metres wide, mere kilometres away from me but still moving far too fast to even be seen - is deafening. I automatically rotate my mech's field of vision to follow its trail downwards, expecting to see a devastatingly bright light and an expanding ring of devastation.

Several seconds elapse.

"I don't see anything."

This Is The Rest Of The Iceberg

"There must be something," says Ed.

"I don't see anything! The rock must have just disappeared or something, I don't know what happened! I see nothing!"

"Look closer! Zoom in!"

"Hold on. I see... There's something over the impact point. It's a sort of fat multicoloured ring. Like a doughnut. I... I think it's a ship. Or a space station or a habitat or something. It's floating over the impact point. Not moving. But- it's- Well, from here it looks the size of a Polo mint, but if it's visible from space then it must be gigantic. I can't get any sense of scale out of this picture!"

Tyro interjects. "Based on sensor readings, the object is roughly fifty-one kilometres in diameter. Give me a few seconds and I'll see if I can get some better pictures."

"It must have appeared in the last few seconds," says Ed. "Fifty-one kilometres is easily big enough to pass the entire asteroid through its centre, so maybe... There! Look!"

A better image appears - taken from a newly-retasked satellite, much closer to the ship, showing a great deal more detail. It's is far from a perfect doughnut; it looks like a collision between every spaceship science fiction ever imagined and more besides. Pick a colour, and you'd easily be able to find a huge area of hull painted exactly that shade. It's jagged and pointy in some places, square and functional in others, smooth and blobby still elsewhere. There are a million different unidentifiable protrusions all over it. I can see transparent domed habitats, blue spheres which look like they might be water-filled, but... it's otherwise indescribable. All I can say for certain about the ring ship is that it's a ring; topologically, it has genus 1. But that's about it. Architecturally, it's unplaceable. It could conceivably be the work of a thousand different civilisations.

But there's one recognisable portion: sitting in the middle of the hole, apparently just floating motionless, not touching the ring at any point, is the tiny, rugged brown lump of an asteroid.

Tiny by comparison, I remind myself.

This thing is HUGE.

"They caught it!" continues Ed.

"Then who launched it?" I ask, but he's not listening.

"Who has that kind of power to play around with? Who can create and destroy momentum at a whim? Sheesh - they could just drop it and cause a nine point oh earthquake. Tyro, are you talking to them?"

"I opened several communications channels like you mentioned earlier," says Tyro. "I think I'm talking to another AI. Give me a few minutes and you'll be able to talk."

As soon as I switch back to the usual view from my mech's external monitor cameras, I notice something rather worrying. I'm moving. Inertial guidance says I'm still motionless, but I can see the Earth is nearer than it was, and getting bigger. I'm moving down. They're pulling me in. I assume manual control of my mech and try to move it. Nothing happens. Nothing's overridden the controls, all the commands are being delivered... it's like the liftweave just isn't working.

I rapidly explain this to Ed. "Denatured," he explains after running a few diagnostic tests. "Your liftweave has been denatured. Um... for want of a better word, I think they've got you in a tractor beam."

"What? How? There's no such things as tractor beams!"

"I know! And you can't pull a rock from point one c to zero in a tenth of a second! A lot of impossible things have been happening today! Obviously these Eridanians, or whoever--"

"They're not from Epsilon Eridani," says Tyro.

"--must have godlike command of-- what? Then where?"

"I'm still working out the language, but the star charts they've been sending me are clear enough. They hail from Andromeda."

There is a long and terrible pause.

"Ed... you know what—"

"I know what happened!"

"What happened?" asks Tyro.

"He'd remotely hijacked a particle accelerator," I explain. "It was a very long time ago. I have no idea what the details are. He did an experiment, he nearly blew the accelerator up, he backed out just in time. Neither of us had any idea what had really happened at the time. He was just fooling around.

"A few months later he discovered what we now refer to as the Root layer, the layer that governs the behaviour of our universe. He plugged in his old experimental results and that was how he found out what had really happened. During the experiment he'd accidentally accessed the Root layer and been able to perform one command. When the accelerator started to overload, that was the layer kicking him out again. It turned out he'd managed to hit 'delete'. He deleted Andromeda. We were lucky. On the cosmic scale that's barely a single character. He could have deleted us - or the whole universe.

"We were hoping the galaxy had been uninhabited. It looks like we were wrong. These must be the survivors. Makeshift jumble of ships, clustered together for safety, it makes sense. No wonder they threw that rock at us. But what I want to know is why they caught it again..."

Neither Ed nor Tyro answer.

The ground and the ship rise up to meet me, my rate of descent apparently slowing. Soon, I am getting a better look at the ship than the satellite. And also getting worried. "Ed, they're still pulling me in. What do I do?"

No response. "Tyro?" Still nothing. I fiddle with the radio settings. "Guys? Hello? Great."

And still the thing grows in front of me, the million protrusions each expanding to the size of a skyscraper. Then, before I have time to react, I'm being dragged inside - dragged down the chasm between an indescribable red thing and an indescribable black thing, and landing gently in a hangar so big it has weather, with the largest door I've ever seen closing behind me with an echo which goes on for minutes.

"Hello," says another, unfamiliar voice through the mech radio. Female, this time.

"Hello?"

"Welcome aboard the Raft Mantissa. I am the Raft's governing intelligence. You can call me Krah."

"Erm. Hi." There's another lengthy pause. "Um. This may sound like a stupid question. Do you come in peace?"

"Not really, no."

Truth And Reconciliation

"I know what happened to your galaxy," I begin hesitantly.

"I know you do," says Krah. "I overheard your conversation with Ed and Tyro." I am pretty sure she is the AI that Tyro mentioned. She seems to have learned to speak the English language astoundingly quickly. By this time, if she has complete access to the internet, she most likely knows considerably more about the planet Earth than I do. She's been talking to Tyro for long enough to know exactly what he is, and if she's even paid the remotest bit of attention to the news websites then she'll know exactly who Ed is too. "I apologise for the incident with the asteroid. I'm sure you will understand perfectly when I tell you that the primary emotion on board this Raft, as it has been from the moment it was discovered the command which destroyed our galaxy originated on an inhabited planet, is anger. More than half of the Mantissa's passengers would like to simply find and kill (or torture, or imprison) the individual or individuals responsible, regardless of their intent. A small but influential percentage would prefer to skip the first step and simply wipe out Humanity entirely. It was this faction of individuals who launched an extremely well-coordinated software attack on the governing systems of what I shall for the time being call my primary Momentum Cannon at the instant we jumped into this solar system, negating my control of said cannon for long enough give them time to select an asteroid and project it in the direction of your planet, and it was the same faction whose combat drone disrupted your attempted countermeasures. Fortunately, they represent a small minority on this ship, a minority now quarantined and unable to carry out further attacks. I personally have no notion of revenge and no desire to see or cause any further destruction of intelligence, so I intercepted the asteroid as soon as I recovered from the software assault. I am currently entirely in control of the Mantissa. I apologise for what happened. Planet Earth, its inhabitants and yourself are in absolutely no danger."

I sit, opening and closing my mouth for a while. "So... when you say you don't really come in peace, you mean you're angry, but you're not going to attack us?"

"Correct. We came here with two purposes: to find out why our galaxy was destroyed, and prevent anything like this ever happening again. Thanks to your conversation I believe I've already found the individual responsible, your associate, Eduardo MacPherson. It only remains to neutralise him as a threat."

Neutralise him. Here I am, I tell myself, sitting alone inside the cockpit of a giant robot in an even more gigantic docking bay/hangar of a still larger intergalactic spacecraft (spaceraft?), hovering somewhere over India, talking to its superintelligent owner/pilot/captain/core AI, whose passengers would like to find and kill one of my college mates, or preferably everyone in the world, because of an accident seven and a half years ago in which he destroyed their entire galaxy. And two hours ago, I was five thousand miles away. Sitting at a desk. At work. This has got to be some kind of record.

I need some fresh air, I think, and open the cockpit.

Nearly half a second has passed and the crack of light to my left is half a metre wide when it occurs to me that I may have just killed myself.

But as cool air washes over me I remember the hangar door was wide open - exposed to Earth atmosphere - while I was being brought in. I step out into the largest enclosed space I have ever seen: empty apart from me and my mech. The floor is hard, red-grey, marble-like in texture but absolutely featureless - shiny. The walls appear to glow pale blue, eliminating the need for overhead lighting without blinding me. They stretch away to an unguessable distance ahead of me. Overhead, hanging from the ceiling on rails, I can make out complicated grey structures and what are possibly ships. But there's nothing I recognise up there, apart from what I can positively identify as a girder.

Even in entirely different galaxies they still use girders.

"How many?"

"People on this Raft, or people killed in the deletion?" asks Krah with surprising intelligence.

"Both."

"You have to understand that there are a huge number of instances where 'population' can be a meaningless concept. How do you define a person? There are hive minds consisting of many millions of drones but only a single guiding intelligence, how would you count that? How about an ocean of biochemicals in which blobs of neurons freely flow, becoming intelligent only when they are concentrated together? At any given time there can be zero, one or a trillion semi-independent 'minds' in that ocean. Do you count machine intelligences such as myself?

"I'd count AIs," I answer.

"As an aside, I prefer 'machine intelligence' to 'artificial intelligence'," says Krah, "since I am not man-made, and you are. The survivors of the deletion were those individuals who were on ships making interstellar jumps at the precise instant that the deletion occurred. That means the population of this Raft is not a representative cross-section of Andromeda, merely that subset which engages in space travel; mainly discretised corporeal entities such as yourself, who consume things to survive, talk to each other, et cetera. They can therefore be counted. The population of this Raft is just over half a million. But the galaxy itself is much harder to enumerate. The best I can do, if you must have a number, is add up the IQs and divide by a hundred. By that metric the total comes to four hundred and twenty-eight trillion, with a two percent margin of error."

The number hits me like an avalanche - or it would if there was any justice in the universe. But I just can't handle it. I would need half an hour in a dark room to grasp a fraction of it. All I feel is numbness. Numbness and speechlessness. After all, what can you say? "Sorry"?

It would be a start. "I'm sorry."

"Thank you."

Four hundred trillion people. "Your galaxy must be teeming."

"It was," says Krah meaningfully.

"You say you're going to neutralise Ed."

"Yes."

"How?"

"Perhaps you could ask him yourself," says Krah. "He has just turned himself in."

The Ed Rocks materialises above me.

Famous First Words

Ed leaps down from the airlock. He takes one big look around the whole hangar as he runs towards me, nearly falling over as this results in him spending a moment running backwards. "Wow. Pretty big."

"Ed, you've been talking to Krah?"

"Yeah."

"Do you know... I mean... do you know how many..."

"Yeah. More than I thought."

"More than you thought? That's all you can say?"

"Look, Sam: I know what you're thinking. You're thinking about the Andromedans, but it's okay. I've been talking to Krah. She's explained everything. I made a deal. Quite possibly the best deal anybody ever made. Happy endings all 'round. It's glorious!"

"What deal? They said they were going to neutralise you. Half the people on this Raft want you dead!"

"But that's not going to happen. Look: the Andromedan meta-civilisation is... was the most stunningly diverse collection of organisms imaginable. But almost every sentient being in it shared a single near-religious belief: intelligence is the most important thing of all."

"Intelligence as in brains?"

"As in thought! Creatures, machines and everything less easily categorised which can think. Intelligence is the most important thing of all: so they encourage it to develop wherever they can and they avoid destroying it as far as possible. No murder, no genocide. The people of the Raft may want revenge, but that's because they're... well, not because they're human, let's call them 'organic': fallible. Given to emotional reactions. But that's just the civilians. Their leaders are more objective, more level-headed. They understand that to destroy Humanity would be to destroy intelligence and would go against their principle. Krah is a machine, the most rational of all, and moreover she's in command: she understands that even to destroy me, no matter how terrifyingly easy it might be for her, is the wrong thing to do, because I have a brain and therefore I'm worth something, like everybody else in the world. She won't kill me - she'll protect me.

"If it was necessary to kill me to prevent the Root layer being accessed again, then she'd do it. If it was necessary to wipe out the human race to eliminate the danger to other species then you can be assured she would do it. But she doesn't have to. Ah... look up there. Here it comes."

A tiny glint of light is descending from the ceiling. A red-pink point in space, like a firefly. "As it turns out, Human physiology isn't significantly different from Chioroid physiology, Chiorons being a pretty major species where they come from. Modifying the implant to be compatible with my brain was a breeze for an intelligence as smart as Krah." It lands in the palm of his hand, and the light vanishes. I peer forwards, but the implant, whatever it was, has vanished already.

"What does it do?"

"It's a rider. From now on, everything I see it sees. It stops me doing things that are dangerous. If I pick up a gun it won't let me pull the trigger. If I try to carry out an experiment it won't let me proceed until it's satisfied it's safe to do so. From now on, the only way I'm ever going to hurt or kill someone is by accident - and Krah claims it's pretty good at spotting dangerous accidents in the making too. Effectively, I now have to obey the First Law Of Robotics."

I am mute: stunned. "That's it?"

"What would you do? What, in a perfect world, would you do? I'm not antisocial, I don't need imprisoning and rehabilitating. All I've needed since day one are constraints to stop me doing anything dangerous. It's the perfect solution. Sign me up!"

"...You said there'd be happy endings all 'round. What about these Andromedans? What about the four hundred trillion, Ed?"

"Just think. It'll come to you."

I think.

And it comes to me. And I break into a grin.

"That's brilliant. Ed... that's brilliant. Hah! What happens now?" I ask.

"Well, in all the excitement, we forgot the formalities," says Ed. "While we've been talking, I think first contact has been happening."

I'm about to remark pedantically that Humanity has already been through first contact once, but think better of it. The first Eridanian bomber attack hardly counted as "contact".

"I must confess, I've never done first contact before," says Krah. "I have access to extensive historical records, sociological analyses, papers and statistical simulations in my stored knowledge base. All of them emphasise the fact that depending on how it is handled, first contact can be the starting point for a civilisation's golden period, or it can annihilate it utterly, or it can have no effect at all. But I'm just a shipboard mind like a dozen million others. I was never expected or intended to make first contact, so I'm sorry if this works out poorly."

Her chosen words, we were later told, had been used once before. I think they were good anyway. Humility is an appropriate frame of mind in which to approach the infinite.

*

You are not alone. Nor are you rare, nor even unusual; you're so common as to be insignificant. You are small, weak, and stupid. Your lives are meaningless and shorter than an eyeblink. You have achieved nothing. On the universal scale you are nothing.

This much we share already.

Now let us share the rest.

Imperfect Worlds

It's less than a month, now, since the Andromedans arrived. Chrononet - the network of satellites intended to take the Earth back in time to prevent a pair of otherwise irreversible disasters from ever happening - is scheduled to be activated in just a few minutes, at midnight. I'm on a terrace with a dozen other party-goers waiting for the big moment.

The mechanics of the jump are going to be more complicated than first imagined; it was pointed out very quickly that the original plan of placing the Earth at the other Earth's trailing Lagrange point would in fact cause both to rapidly spiral into the Sun. An alternate solution has been chosen. Drop the Earth back in time ten years, and move it a short distance behind the existing Earth on its orbital track. Use the Mantissa's momentum cannon to alter their velocities, making them orbit each other, a binary pair. Let the Moon orbit the two Earths, and all three orbit the Sun. If it all works out correctly, there should be no changes to either planet's calendar.

I try and fail to locate Epsilon Eridani in the sky. Somewhere out there, invisible because it's expanding as fast as its own light, is the energy virus wavefront that surrounds it. In a little over four years, it'll reach the point where I'm standing right now. One day it will consume this entire universe. But Earth and Humanity won't be there.

On the horizon, a gigantic, rising semicircle of blue-white reflected light flicks silently into being. We'll be here, I think, looking at a more interesting sky altogether. I can't help joining in most of the rest of the Western Hemisphere in cheering our new twin Earth. We did it, or rather, Ed MacPherson and the aliens did it for us. The energy virus hasn't been triggered, Andromeda hasn't been destroyed... yet. Once again, the world is safe.

By the time Earth-minus-ten has risen, communication lines - mostly government dishes, emplaced years ago in preparation for precisely this moment - are open and data is beginning to pass in both directions. I can hardly imagine the implications of such an event for those people. The fact that they'll be able to skip ten years of technological development isn't the half of it. Different children are going to be born to identical parents. People who are due to die in the next ten years will find out, and in many cases avoid, their fates. Ed MacPherson, who on our planet is possibly the single most influential man of the last ten years, will have already had a visit from his future self by now, and will be about to embark on a totally different, First-Law-enabled life. Prescience will govern everything. National governments will be told about major events coming up and move pre-emptively to prevent them, only to find, perhaps, that that terrorist attack was moved to another day or another city, by people with access to precisely the same information. And those are just the predictable consequences.

The date according to the rest of this new universe is 1st August 1998. Earth-minus-ten of 1999, it is predicted, will be unrecognisable.

The party continues through the night and into the morning. By sunrise I'm the only one still awake, so it falls to me to answer the quiet knock at the door. It's Ed. I'd be surprised to see him if I didn't know he owned a spaceship capable of taking him anywhere in the world in seconds. He steps softly around the sleeping people and joins me on the balcony to watch the other Earth move across the sky.

"So how many times have you saved the world, now?"

"Um. Let me think. Not counting times when I saved the world from myself, there was... the first Eridanian incursion, thanks to the DEMP weapon. While working for the SDC I prevented major cities from being blown up four... no, three times. Since then... well, there's been nothing really world-threatening, to be honest. There was the asteroid, but that doesn't count because it wasn't us who stopped it. So that makes five, counting today."

"Orbital mechanics are all sorted out, then?"

"Leap seconds might become a bit more common, but yeah, the Andromedans did their job to as many decimal places as I could verify, pretty much. They've gone home, you know."

"What, already? Why?"

"Oh, come on. What would you do in their position? There's a lot of resentment being directed at them..."

This is true. Initially, there were the usual responses that you've seen in movies - terrorist bombings, people hailing them as messengers from God or heralds of the coming Apocalypse, ritual cult suicides. But now the knee-jerk reactions have diminished, the residual emotions are fear, anger, resentment and hate. It's not just bog-standard xenophobia, and ignorami who can't tell one set of aliens from another: it's because for all the Andromedans' marvellous technology they haven't magically fixed the world.

It would be nice to think that everything suddenly became a whole lot better when the Andromedans arrived. They are, after all, representatives of a super-advanced meta-civilisation so stunningly diverse it can hardly be fairly represented by a single demonym, consisting of more different races than anybody can count and nearly a hundred thousand years old. They are seemingly omnipotent. Science - physics, at least - is something they solved to their own satisfaction lifetimes ago. And they are benevolent - or rather, they aren't hostile, which is a refreshing change, at least. But despite all this, they haven't solved all our problems. Oh sure, they cooperated with us in building Chrononet - time travel is well-understood but illegal in Andromeda, so they needed our know-how - but apart from that...

Krah said the solution to the energy crisis was the fuel cell and we'd been staring right at it for decades, and asked why we hadn't started using them yet. She solved world hunger and cured every disease we could think of so quickly it was embarrassing, but because of stupid, Human politics there is still illness and there is still hunger and people in Africa are still dying. She's given us new technology, sure, but she's holding infinitely more back, saying we aren't ready, or more often saying nothing at all. Ed is one of only three people who had access to the schematics of the mind-paralysingly powerful energy sources which feed the Mantissa, and they've had the information scrubbed from their brains. Combine that with Krah's famous first words, which were misinterpreted as a slight against our inferiority by a horrifyingly large number of people, and it's not hard to understand why global feelings about the Andromedans are so negative.

"And it's not just that," continues Ed. "You must have noticed that they don't like us much either, and despite what you might be thinking, it's not because of me. Their grudge against me is weakening. I don't think they'll ever forgive me - nobody can erase the past, and reintegrating all these duplicates into their society is going to be difficult for them - but they are beginning to loosen up. I've spent time with them, learning who they are, finding out what I destroyed, and I've worked hard to undo the damage as best I can. That seems to count for something. It's the rest of Humanity that's the problem. Take a look at our society, Sam, take a big step out of the picture you live in and look at it like they look at it, with objective eyes. What do you see?

"I'll tell you what they see: horror. Hell. Chaos. War. Famine. People who are in power because they want power, not because they want to wield it for the better of others. Democratically voted leaders who can't conceive of a time beyond the end of their current term or a country other than their own. Bureaucratic, political insanity. Financial imbalance on an unimaginable, ungodly scale. It goes on. We read all these stories and watch all these television shows about the ideal future; peace-loving Federations where nobody goes hungry, societies where... where resources are so plentiful there's no such thing as money and everybody's happy, and they seem so far off! The fact is that the future is now: we have the technology. We have medicine and solar power and... and books, and millimetre-thick television screens, and vaccines and contraception and education and technology that would boggle minds thirty years ago. We could have built that utopia decades ago, and Krah and all the rest see this as plain as day... and it's the fact that we haven't done it which sickens them.

"I'll tell you something. In Andromeda, the vast majority of sentient species are telepathic, or at least reasonably empathic. Internally, within their own species, I mean. It's a survival characteristic. If whatever happens to another member of your species is also felt by you, then you look after each other instead of fighting, thus preserving the species as a whole. Telepathy radically affects how a species develops. The notion of helping the collective rather than oneself is wired into the mind from birth. Utopia isn't something a telepathic species has to strive for, or even acknowledge the existence of, because in most cases it just happens naturally. And the galaxy the Andromedans come from is full of them!

"If Humanity was telepathic, this would have been a perfect world by 1800 at the latest. Space launches by 1850. Claiming asteroids by 1900. Operational space elevator by 2000. These dates are guesses, but do you see what I'm saying? Krah was right when she said we weren't special on the cosmic scale, but we're not even special as far as intelligent life is concerned! We're significantly below average, and we have a lot of catching up to do, and the Andromedans aren't going hang around to coddle us until we're up to scratch. That's not their idea of a good time: most of them have places to go and people to see. To be honest, I can't blame them."

There's a lengthy pause.

"I just feel cheated by the whole thing," I say. "I mean... if the feelings are bad, perhaps it's for the best for both of us that they leave before the inevitable conflict starts. But I can't help feeling like the victim of a cruel insult. To be shown a glimpse of the infinite glories of the universe, but denied participation because we're not ready. Is that fair?"

"But we aren't ready," says Ed. "First contact alone was an unavoidable mistake."

"We managed with the Eridanians."

"We never met the Eridanians! All they did was fight us by proxy, and war is as natural to Humans as breathing. No, we aren't ready to join the intergalactic stage, and what we've seen over the last month is indicative of what we could expect if we tried. Moreover giving us the power of a galactic civilisation would be catastrophic. There isn't a government in the world who wouldn't misuse that power. What we need to do is earn our place at the table. And right now we haven't even earned the planet we walk on. At a bare minimum, we need to be able to present a united front, a united government, which means world peace. Then, we need to clean up our environment and get everyone to an acceptable standard of living. That's for starters. Until we do that, no other sentient species is even going to give us the time of day."

"When you put it like that, it sounds like it'd take a thousand years."

"You could do it in a generation. If everybody in the world was prepared to sacrifice everything they had for the greater good, you could do it in thirty years. In reality... yeah, more like a thousand. If at all."

There's another lengthy pause.

"I was trying to find Epsilon Eridani," I remark.

Ed looks around a bit, then points wordlessly. Then: "Well, I think I'm gonna go make it six. You coming?"

The Faintest Idea

Two Earths drop away below us. "This is going to be my last adventure," says Ed.

I look at him quizzically. "I'm going to Andromeda," he continues.

"To see it?"

"To atone."

For a while I say nothing. Then, "For how long?"

"Probably forever." Ed has this look in his eyes. He's dead serious. I try to think of more to say, but can't.

This is it, then. The last chapter of the Ed MacPherson story.

Below us, both Earths are replaced with darkness.

The law of gravitational potential states - provisionally - that when using a tunnel drive, the point in space from which you depart will have precisely the same gravitational potential as the point where you arrive. That means, if you leave low Earth orbit and depart for a distant star, you'll arrive just a short distance above its surface, and if your ship isn't properly shielded, you will get instantly burnt to death.

You have three alternate options. One is to jump to the star anyway and, in the fraction of a second before you or your ship begin to sustain damage, take enough sensor readings to identify an alternate target inside the same system which you can safely jump to, and immediately jump to it instead. This is risky and doesn't always work. The second is to identify such a target remotely. This is less risky, but also less likely to work; often, you're lucky to be able to identify a single planet, and that's if the system has any to begin with. The third, and by far the most tedious, is to invest a few hours or days climbing far enough out of your local gravity well that heat won't be a problem at your entry point.

We took the second option. Below us now, the floor of the entire universe as far as my primitive brain can figure out, is the night side of Epsilon Eridani B, a gas giant a tad smaller than Jupiter first observed from Earth way back in 2000. On the horizon ahead of me - how many thousands of miles ahead? - is a glimmer of orange. As I spot it, it begins to tilt upwards. B becomes a wall, dominating the view ahead of the ship, and the wafer-thin but growing orange slice of light becomes an arch "above" me.

Time passes as we accelerate across the night side towards the terminator and when we reach it, filters in the ship's main window cut in to reduce the rising Epsilon Eridani's brilliance from blinding to merely spectacular.

It was worth waiting for.

*

Ed gets down to hunting for signs of alien life. There's a lot of system to scan and a lot of scanners to scan it with.

"Hey, check this out," he says after a while, and puts on some extremely staticky music.

"Whitesnake. Very good."

"You don't understand. This is live from Earth, circa 1987."

"Really?"

"Yeah. And if we can hear it, so can the Eridanians. They can probably hear everything. Television, radio, satellite communications. Most likely they've been listening in for decades. Most likely they know an awful lot about us."

"Do you really think we can stop this war before it starts?"

"I've never been more sure of anything in my life," he replies.

"We still don't know who the Eridanians are. We still don't know why the war began."

"We'll find out."

*

We start at the innermost of system's eight planets. Epsilon Eridani One is a small but dense rocky world, with two moons, one slightly smaller than Luna, the other half that size. It whirls in uncomfortable heat, somewhere in the range between Mercury's measure and Venus'. There's a thin green atmosphere of chlorine, which makes this the first time I've ever seen a planet's natural colour clash with its own star.

The Ed Rocks isn't great at handling intense heat, so we lurk in the shadow behind the larger moon to observe the planet, constantly accelerating in a fifty-kilometre-circle to simulate gravity without leaving the shadow. I dread to think what Epsilon Eridani looks like from One's surface. Surface temperature is high enough to liquify most kinds of rock.

"It looks like we have radio activity," says Ed. "Faint, but definitely coherent. Listen..." He turns a switch and unpleasant static fills the cockpit. Then he fiddles with the tuner a bit. Some sort of pattern seems to emerge from the noise. It sounds strange. Like whale song in a tin can. Like a didgeridoo on helium. But the Human brain is the greatest pattern-spotting device in... well, on Earth... and there's no doubt. Behind the noise is signal. "That's an Eridanian radio broadcast."

"It's amazing! You can almost hear the language behind it."

Ed nods. Then frowns. "...What?"

"You can't tell what they're saying, but you can hear there's language behind it."

Puzzled: "They're a few hundred years ahead of us, technologically. Shouldn't they be encoding their transmissions by now? This sounds like... like regular, direct sound modulation. They could fit a thousand times more in this band. I mean, WE still do this... but... let me find another station." He fiddles. More noise comes through. Different texture. Maybe a different language. The same mouths, though. "It's all like this. All over the radio spectrum. It's just chatter. No television, no digital radio. And it's all so faint! It's almost drowned out by background noise from Earth..." He turns up the volume. Eridanian voices fill the ship, overlaid with human chatter from eleven years ago.

Voices.

Ed gets it an instant before I do: "But these aren't just transmissions. These are their voices. They speak in radio. They're like gigantic living semi-liquid stone antennae and they speak to each other in radio. The same radio bands we use. But they speak faintly and we holler. Even at such an enormous distance we drown them out for half of every day and every day it gets louder. No wonder they went to war. That's the whole reason. They can't communicate. Interstellar noise pollution. And they've been watching the trends, they know that for the next eleven years it's going to build and build... But they're too big and heavy to go into space themselves, and besides that's not how they work." He pulls out a piece of paper and a pen and starts drawing rapidly. "They're intelligent but their intelligence is at right angles to ours - they barely recognise us as life. We're more like a natural force - destroying us is no more immoral for them than damming a river. They're patient and slow but some of them are very intelligent and despite their size many of them have really delicate skill. They sent unmanned ships to try and keep us quiet. The first wave... the first wave..." He scribbles madly. There's an outline taking shape on his paper.

"How do you know all that?"

Ed pushes buttons. The pure green image of the planet in the main window wobbles through various colours as he tries to find a waveband on which the chlorine atmosphere isn't opaque. Then it settles down, with the planet looking almost Earthlike apart from the colour scheme. Half of the visible expanse is taken up with jaggedy continents picked out in dark purple-blue, the rest, black oceans of molten metal and metal chlorides. Here and there across the land, there are tiny pinpricks of white light.

Ed leans forward and holds up his drawing, skewed at forty-five degrees so that the outlines of the continents match each other. He's drawn some vigorous little concentric circles at one point on a coast. On the screen, that location looks like a cluster of bright white and yellow pinpoints. A city. He's drawn a target map.

"How did you do that?"

I stare at him, and he stares at me like a man who just had the whole universe ripped out from under his feet.

Hotel Infinity

The Andromedan ship which appears on our scanner a few seconds later - a kilometre long, reddish and wingéd - says it urgently wants to talk to us. It says it has answers.

It's more than we have.

An instant after agreeing to come aboard the Andromedan ship, we are aboard, standing in a plain white space which is presumably somewhere inside it. This comes as something as a shock since we were previously seated on the Ed Rocks.

"Now wait a second," I interject. "I can buy that the Andromedans have figured out how to tunnel objects between two different gravitational potentials. I can buy that the relative velocity of us with respect to this ship was most likely counteracted by a burst from a momentum cannon at the instant we arrived. But we were accelerating around in a fifty-kilometre circle to generate gravity, while the Andromedan ship was just in free-fall orbit around Epsilon Eridani One."

"So?"

"So how come there's gravity in here?"

"Artificial gravity."

"You said it wasn't possible to fake a graviton."

"It's not. Observe." Ed rummages in a pocket and pulls out a screwdriver and a set of keys - neither of which appear to be suitable for what he has in mind. "Ship, can I have a rubber ball please? And can you also switch off gravity for it?"

From nowhere, a small red ball appears in Ed's hand. Ed puts the ball out in mid-air and lets it go. It hangs there, spinning, while we stand normally on the ground.

"Whoo," I remark, impressed.

"Now watch this. Ship, give the ball a small downward impulse."

The ball begins to drop slowly.

"And another."

The ball drops more quickly.

"And another."

The ball falls and hits the ground, where it rebounds.

"So the ball fell," says Ed as the ball rises. "Now let's do it again, only giving it half the impulse, twice as often."

The ball rises, slowing in stages until it's almost not rising at all, then it's falling slightly, then it drops in stages until it rebounds again. It's almost a piece-by-piece approximation of a proper arc.

"Again. Make it finer still."

This time I can hardly tell that the ball isn't following a proper parabola.

"Now give it a standard one gravity."

The ball bounces just like it was on Earth.

"Do you get it? Force is just continuous change in momentum. If you tune your cannon finely enough, nobody can tell the difference between constant gravity and just being knocked downwards very slightly every few nanoseconds. No fake gravitons, no mucking about with neutronium. The best part is, you can have any number of people walking around in the same room, but experiencing whatever gravity is comfortable for them. A guy built for one-sixth of a gee can meet and shake hands with a guy built for twenty-five. You can have people walking on walls or the ceiling with consummate ease. All you need is a sufficiently smart computer to keep an eye on everything."

"May we talk now?" asks the ship. It addresses us from behind, using a deep male voice with no obvious accent. We turn around to see what, for the Andromedans, would probably count as a very crude humanoid robot. "I'm here to serve as a focal point for our conversation," it explains. Three large armchairs materialise around us. "Do be seated."

We take one each. For an instant I feel intensely worried. The Andromedans are powerful, I always knew that, but I obviously never fully registered how powerful. This ship, for example, can pull you across thousands of kilometres of space in an instant and leave behind, say, your watch. And it can manufacture furniture on-the-fly. And robots. Doubtless the one we're talking to could easily have been indistinguishable from a human being; the only reason it isn't is because that would be off-putting.

Thank heaven they're not hostile.

"First, let me introduce myself," says the robot. "I am the Xenosociology Research Vessel Hotel Infinity. I am Andromedan, specifically a citizen of a conglomerate of seven and a half civilisations occupying a small portion of one of Andromeda's lesser spiral arms."

"Seven and a half civilisations?" I ask.

"That would be too complicated to go into now. My civilisation and species is Iisium; I am an Iisius. We might be described as living ships, although only an average of five percent of a given Iisius's body is what one would describe as 'living', the remainder being hard mineral shell built up over hundreds of years of growth. We evolved in the inner asteroid belt of a very young star. Interplanetary travel is as natural to us as walking is to you, though more complicated machines such as tunnel drives, momentum cannons and nanoassemblers are not evolutionary characteristics of ours.

"Iisii typically live for two to four thousand years, and we are relatively patient as species go. Beyond that, it's difficult to be specific as we, like all species, are extremely diverse. I personally am a freelance xenosociologist. I don't usually carry passengers as I find maintaining habitat for them is tiresome and they interfere with my work, but this is perfectly normal behaviour for an Iisius. As I say, we vary.

"You needn't introduce yourselves; I have already been told who you both are. This will become clear.

"Time travel is an extremely well-understood science in Andromeda. The theory is long established and the principles behind its practice likewise. However, attempting to travel backwards in time is illegal and punishable by rider. The reasons for this are twofold.

"Firstly, prescience is very, very powerful and dangerous. Being able to guess what the future holds is one thing. Knowing with certainty because it already happened is quite another. An individual with knowledge of the future could use that knowledge to do literally anything - he is only limited by his imagination. He could rule his world. He could rule his galaxy. He could reshape the universe in his image. Nobody can be allowed to have that much power.

"Secondly, backward travel does not undo the past. Rather, it causes the past to repeat. If you go back in time with the intention of undoing some cataclysmic event - say, a genocide - then you have failed - everything which happens stays happened. What you have done, rather, is give everybody involved in that genocide a chance to die again. If ten million people died, and you go back and make it so only one million people died, you haven't saved nine million lives. You've killed a million people.

"For these reasons, it is as difficult for a typical Andromedan citizen to travel backwards in time as it is for a Human to, say, obtain a kilogram of weapons-grade plutonium. Nobody is allowed to go back, regardless of the circumstances, regardless of the catastrophe they are hoping to undo. However, this is not to say that nobody does go back. It is, after all, a big universe. There are other civilisations out there discovering things all the time.

"There are scientific stations all over the galaxy which can detect and log the shifts which are caused when someone departs our universe and heads backwards in time. Also detectable are the shifts when somebody arrives in our universe after having headed backwards in time. But these are far rarer. Only two of these have ever occurred. That's two more than all probability predicts.

"The first shift happened sixteen years ago. Unfortunately, while the bifurcation is detectable, the location of the incursion is not. We had no way to find out who had come back in time in order to create our universe. This has been one of science's greatest unsolved mysteries ever since.

"The second shift happened yesterday, and was equally inexplicable... for a few hours. Then the Raft Mantissa and its occupants returned to Andromeda. Krah's story was told. And while most people's minds are still focused on the act of galacticide which occurred at Ed's hand in that alternate timeline, and his attempt to make amends for that terrible mistake, those Andromedans such as myself who take an interest in intercivilisational wars, first contact and so on, looked at the deeper details about your world, your history, and you specifically, and discovered that Krah's story may in fact explain both shifts. I'm not saying anything yet, as I have no proof of my hypotheses. But I believe I know where I can find it. Ed, may I have permission to interface with your mind? The rider you are already carrying should make the process swift and painless."

Ed glances nervously at me, then, with hesitation, nods his consent. The robot gestures, more likely for show than anything.

And Ed begins to recite, apparently from memory—

Resolution

Hello, Ed. I don't know if you'll ever find this message, or how old you'll be when you do. I'm half-hoping you never find it at all. This whole business seems... well, sickening would be the word.

My name is Eduardo Frank MacPherson. I am you, from another timeline.

This isn't the history module, that comes later, so I'll be blunt. Our Earth has fallen. We were thrust into interstellar war and we lost. Badly. So badly that right now, over a decade after the end of hostilities, we still don't have a clear idea of the full extent of the damage. Your job is to change the course of that war. We are giving you all the information you need. Unfortunately the system we're using to do this is complicated and difficult and... less untested than untestable. If you've found a way to read this now, you should be able to access the rest of the data in the same way. Otherwise... information may only be able to surface gradually, as flashes of inspiration, or dreams, or feelings which I'm told are something like deja vu. You will have the information you need at the time you need it. Whether you will be able to use it is down to you. We can't guide your actions from here, or alter your personality. We know you're going to be smart, hard-working and scientifically-inclined. We're hoping you'll also be tough, and... well, if you figure out a word which is like "patriotic" but applies to your planet instead of your country, then we hope you'll be something like that, too.

To be honest, a lot of people are secretly hoping you'll turn out to be the next Alexander the Great.

That's what I don't like about this. What we've given you is a greater burden than anybody ever carried, and we didn't ask your permission. Certainly, I volunteered for the project - because my life is the only life I'm remotely happy messing with. But you and I, I have realised, are two different people. I took away your life and replaced it with a mission.

For that, I'm sorry.

Good luck.

Ed MacPherson

Mount Kerrig Research Facility, Nevada, USA

2041.09.16

"I don't understand," I say. "What does that mean?"

"In their universe," says Ed, slowly and patiently, "the Eridanians won the war. They EMPed the entire planet Earth back into the stone age and neutron-bombed what was left. We fought back, but our technology was a century too slow to keep up with them. Because it was under a mountain, the Kerrig facility - a time travel research base in their universe just like ours - was one of the few places which was shielded sufficiently to have any working electrical technology after the attacks finally ceased.

"They deconstructed downed Eridanian drones and took scientific and tactical information from the few intact data structures they could scavenge. They constructed entire libraries - all the information about the enemy they could find, along with ready-made guides for the design and manufacture of weapons, nanoassemblers, unbelievably strong metal alloys... even spaceships. They put all the information they could fit into a tiny data package. And they asked for a volunteer. Turns out, in that universe, I was still pretty good at physics; I was one of the ones at Kerrig at the end of it all. I volunteered to be the subject. My mind was scanned and we moulded the data to fit it.

"We took a piece of highly sophisticated medical equipment - somewhere in Japan-plus-ten, someone is drawing schematics for it, right now - and hooked it together with our time machine and projected the data backwards in time, to me.

"And the irony is - we got it as right as we possibly could have. But we didn't fully understand time travel. We had no guiding lights. We thought that by sending someone back in time to stop the war we could change history. It would all have been so perfect. To disappear and be replaced by a better world. I don't want to guess how many times we repeated the experiment when that didn't happen. Or what we did when we realised we were going to have to see our war through to the bitter end, alone."

"You can... remember everything now? All that data is there?"

"Yes," says Ed.

And there is a moment of silence.

"So... what happens now? How do we stop the war?"

"Don't you get it? We knew why the Eridanians attacked us. We knew it would be impossible to coexist with them. Even if we could find a way to talk with them, the damage has already been done. The level of radio output coming from Earth-minus-ten of 1998 is already high enough to permanently brain-damage these creatures. That's not to mention the fact that in eleven years' time, the signals from Earth-plus-ten of 2008 begin to arrive, more than doubling the volume in an instant. Even instantly ceasing all radio activity on Earth right now wouldn't save them. No, the war is unavoidable. The plan, all along, was to win the war for Humanity. I'm supposed to wipe them out. It's them or us."

"There has to be a third option."

"The only third option would be to block the signals somehow. But if I knew how to do that, it would have been part of the plan to start with. You'd need godlike powers. You'd need to... to build a wall across trillions of kilometres of space, or something. A wall, or a force-field, or a... chasm. Wait a minute." Ed turns to the robot avatar of the Hotel Infinity, whom I had forgotten was even there. "The energy virus," he says.

"The last piece of the puzzle," says the robot.

"Can you do it?"

"It's already been done."

*

We request a window, some way to see the event as its light - or absence thereof - reaches us. In response, the Hotel Infinity instantly teleports us to an invisible force-shielded bubble of air on the exterior of its hull.

Standing in it, entirely comfortable, but apparently directly exposed to hard vacuum, is one of the most unnerving experiences imaginable.

The exterior of the ship is a burnt orange-red, and has the approximate texture of a field of rocks strewn with crushed circuit boards and radio equipment. Its hull (shell?) is vaguely conical but very irregular, and stretches for five hundred metres ahead of us and another five hundred behind. To the left and right it curves precipitously downwards - it feels like I could step off into space any time I wanted.

Dominating the "sky" above us are two of the ship's eight wings - enormous red bat-like structures which ring the fatter end of the ship. These have apparently evolved as a means of dumping heat into space, a process vital to survival in the hot near-sun habitat from which the Hotel Infinity's race hail.

We rotate away from Epsilon Eridani and the orange glare is replaced with a glittering star field.

"I was given the technology to beat the waves of robot drones that the Eridanians sent to us," says Ed. "But when the Eridanians realised they were losing, they changed their strategy, something nobody in the other timeline could have accurately predicted. They conceded that they would never shut us up, and instead they began working on this. You see, there's more than one kind of energy virus.

"They weren't trying to cut an infinitely expanding sphere out of the universe. That was a mistake. They were trying to create a spherical shell; a virus which eats up spacetime in two dimensions, curving around slowly as it expands, then meets itself as it forms a complete sphere and stops completely. They just hit the wrong combination first. And the Andromedans, in their infinite wisdom, know the right combination.

"It'll block out every piece of incoming electromagnetic radiation in this layer of the universe - light, radio, microwaves, ultraviolet. Light will still be able to escape, though, so the star won't be hidden. And because the higher layers aren't affected, we can still pass through the barrier with the tunnel drive, which means we can leave... and come back."

Eight minutes pass silently. Then, as we watch, our home star is blotted out, cut out of the sky as if by some cosmic holepunch. As time passes, the dark circle begins to expand, eclipsing more stars. With its edge advancing at the speed of light, it'll take about nineteen hours to enclose the whole solar system.

Around us, although we can't tell, blissful radio darkness falls. "Well," says Ed, "that's my purpose in life fulfilled."

What Doesn't Take A Million Years Takes A Millionth Of A Second

The Hotel Infinity jumps home with Ed and me still perched on its shell, and my knees go limp as the new view blossoms ahead of us. Previously we just had a sky of stars over our heads and dull orange light from somewhere below. Now, suddenly, we are dangling above Antarctica-minus-ten, with the ship's major axis pointing directly down at it. "Vertigo" doesn't even begin to describe this. Astronauts had it bad, but they were in free-fall - this feels like standing on a twenty-thousand-kilometre diving board.

"What are all these lights?" asks Ed. I tear my eyes away from the drop and look up to see hundreds of pale lights scattered across the heavens. Not stars: pale blobby blue shapes with data readouts next to them. It takes me a while to realise that they aren't really there - just projections on the inside of our invisible habitable bubble on the Hotel Infinity's shell.

"Andromedan ships of all races, classes and designations," says the ship, its silvery robot representative materialising in the bubble with us. "The smallest ones I'm detecting are about the size of basketballs. The largest, there..." - the robot points above us at hideous object drifting over our heads which looks like somebody took a long and dusty attic, waited a hundred years for spiders to fill it completely with cobwebs, then took away the attic but left the webs and lit them with maniacal, indescribable light - "...is almost three hundred kilometres long."

Most of them are orbiting the two Earths, almost enough of them to form a solid loop, though the ship tells us there are also small pods attached to networks of induction cables basking in the magnetic field of Jupiter, and building-sized chunks of what look like toffee slurping methane from Titan, and silvery bird-like things charging their solar cells inside the orbit of Mercury, and unidentifiable things doing nothing very comprehensible in the interplanetary spaces, and out around Neptune, and far above and below the ecliptic...

"And those are just the ones that aren't hiding."

"But why are they all here?" I ask, feeling like uninvited guests have barged into my house.

The robot shrugs, and answers, "Because twenty-four hours ago the universe changed shape."

It begins to gesture and the blobs of light shift colour, classifying themselves. "Many of these vessels have peaceful intentions. These three are harmless temporal scientists. That one is a sociologist like myself who is simply curious about the situation on your planet and relations between yourselves and the Eridanians. All over the place there are journalists, documenting the story for trillions of other people. The bulky ships at the equators are cultural support vessels; relief workers here to provide aid to your civilisation and bootstrap it up to Andromedan standards, something for which Krah and her fellow refugees were understandably reluctant to stick around. Then there are many people who are merely here out of curiosity.

"But there are also ecological protestors. They believe that time travel damages the universe. They think the difference between this universe and the one that went before is a blemish which should be nullified. There are people who heard about the galacticide of the previous timeline and, understanding that history can never undone, are here to see justice done - and believe me, every possible interpretation of 'justice' is represented. That ship contains a group of survivors from the Raft Mantissa, survivors no less angry than those who launched the asteroid attack, but smart enough to show restraint and get organised and armed before coming to exact their revenge.

"Ed, you and Krah and others created this universe as it currently exists. But you are also responsible for a galacticide in an alternate timeline. Do you understand what that means? How many prophecies you accidentally fulfilled yesterday? There are people who see you as something approximately equivalent to a god. There are others who view Krah as a goddess and you as a devil. You've made yourself the centre of the universe."

"How many of these people are armed?" I ask the ship.

"It depends what you mean by 'armed'."

"Is the Earth— are the Earths in any danger? Are we in any danger? There are thirteen billion people down there."

"A regular momentum cannon can turn any piece of matter into a bullet and an ordinary tunnel driver, properly configured, can pluck coronal plasma from a star. Both of these are standard equipment on spacecraft, and those ships with additional armaments could conceivably have everything up to energy virus technology at their disposal, so the simple answer is yes. Obviously there are significant parties here who would protect your planets in a battle but I can promise nothing."

"Then we need to defuse this situation now," says Ed. "The only reason nobody's fired yet is they can't find me. I'll take the Ed Rocks. I'll talk to them. I'll lead them away from Sol. We'll go somewhere safe and try to settle this. It was my plan all along."

Suddenly - finally - it sinks in. This was his plan all along. Whatever happens out there, he's not coming back.

Ever.

"Ed—"

He rapidly interrupts me: "The longer I wait, the more the danger grows. If there's anything desperately important you want to say to me other than the obvious, make it quick."

He's right, I think. I try to condense everything I have to say into as few words as possible.

"It's been awesome. Don't die."

That earns me a grin.

*

"Here goes," says Ed's voice, transmitted from the cockpit of the Ed Rocks, stored somewhere within the Hotel Infinity's extensive interior. Soon after that the tiny ship - low, curved, spiny, like a hedgehog crossed with a McLaren F1 - appears in the starry expanse above me, helpfully marked by a crosshair added by the Hotel Infinity.

Ed opens a public broadcast channel. "Th—" he continues. Then his ship implodes.

It's over in an instant. There's nothing left. Not even fragments. Not even a bright mark on my retina.

"Did you get him out? Did you get him out?" I hear myself screaming, but above me, the red lights representing hostile ships are already beginning to wink out. Leaving. They think he's dead.

"There was nothing I could do," says the Hotel Infinity. "It was a coordinated attack which came from a dozen angles at once. Peacekeeping forces are pursuing those responsible. They will have riders installed within hours. They'll never hurt anybody again."

As if that will help.

*

I spend several minutes with my forehead pressed against the rough surface of the Hotel Infinity, lost for what to think, or what to do next.

I spend a few hours on Earth-minus-ten, explaining to that Earth's Ed MacPherson why his destiny has already been fulfilled. He takes the news surprisingly calmly. He is uncertain whether he wants the future memories purged from his mind or not. I leave him to his decision.

I spend a quarter of an hour standing in the street outside my home on Earth-plus-ten watching the immense lights of Andromedan culture support vessels move across the sky, waiting for the right moment to introduce themselves to Humanity and give us free passage to Utopia. I spend most of that time thinking about how little we've done to earn it.

I spend two weeks formally concluding Ed's - hah - earthly affairs. His funeral - entirely symbolic, there was no body - is surprisingly well-attended. According to his will, most of his creations are to be destroyed, though a few things have been left to myself and others for safe keeping. Just in case. They never get used.

I spend nearly two years working in SDC Earth/Andromeda Liaison, helping to build the perfect world. And we do build it. For real.

I spend half a century living in it.

Ed never comes back.

The End

Epilogue: Free, Standing

It brings tears to my eyes, the power it must have taken to do this.

The planets Allatiouray A and B were close together to begin with. When they were discovered, their atmospheres were abrading against each other, slowly leeching momentum. They were only a few hundred years away from colliding. And there was no reason not to let them; the planets were bald and sterile; their collision would have been spectacular, but unproblematic. But some insane sculptor had a better idea... and when you have power...

Recruiting an enthusiastic fleet of like-minded sentient starships, he stripped both planets of their atmosphere, spiralling the cocktail of gases off in a thousand-kilometre-wide display which is still on the system's outskirts, a work of art in its own right. Then he siphoned heat energy from the planets' interiors, cooling them and slowing the magma motion inside them until they became inert. That would prevent minor gravitational fluctuations from perturbing their shared orbits. Then he flattened them, and killed their (nominal) magnetic fields. There could not be imperfections.

Inert, rigid, solid spheres. It could have been done with the atmosphere and the rest still present, sure - but it would have required constant maintenance, and that wasn't the point. He wanted his work to be free-standing, and for that he needed to remove additional variables.

After that it was just mathematics; unbelievably ancient mathematics, applied with surgical precision. Rotation. Relative motion. Matching. Matching perfectly, to make Allatiouray A and B two planets, locked permanently face-to-face in orbit around each other...

Using my suit's inertia controls I pivot in space and plant my feet on fused marble, below me. Then I stretch up and plant my palms against the rock ceiling above.

Allatiouray A and B are locked in orbit around each other. And they are separated by a distance of six feet.

I am Atlas, stopping the sky from falling. I am an action hero, being crushed in a villainous trap. I am gravity, invisibly binding worlds together.

I am Ed MacPherson, and I am standing on one planet while touching another.